2 days & 3 nights in Rome---solo
 

I am going on a tour of Puglia which ends in Rome. I have decided to stay on by myself in Rome for 3 nights (6/3-7/2). I haven't been there for over 30 years so it is almost like never. When I was there 30 years ago, I did a lot...Vatican, Pantheon, etc but I did not visit the Colloseum. Since my time is so limited I am wondering what the best way to see some sights would be---I don't want to be crazy running around or spend a lot of $$$. I think I am willing to forgo visiting the Vatican/Sistine again as I don't want to deal with feeling like cattle in the crowds but maybe should see the Colloseum--I have been reading on here that I need to reserve tickets ahead of time?
Should I look into doing one of those hop on & hop off buses? Tour guide for a day (if so, any recommends for a cheap one---tall, dark & handsome would be a plus)? Just wing it on my own? I am staying at the Marriott Grand HOtel Flora on Via Veneto.
I am sure this question has been asked 100 times on her but search feature fails me. Thanks!

Search works better if you spell "Colosseum" correctly. A "Titles-Only" search turns up eight threads, and a "Search Entire Posts" turns up well over 100. (However, I don't know if your questions are answered in those threads.)

Just got back from Rome a few weeks ago, where we spent 3 days 3 nights, and I think we were able to get everything in. I don't know your specific interests or what time you get into the city, but your hotel seems close (enough) to the Spanish Steps, Trevi Fountain, and the Pantheon (and while you're there, I'd recommend a look inside Basilica di Santa Maria Sopra Minerva) to do them all in one go.

Now for my Colosseum advice: We bought tickets ahead of time on https://www.coopculture.it/en/colosseo-e-shop.cfm. The entrance includes access to the Colosseum and the Roman Forum/Palatine Hill. The online reservation "surcharge" is 2€ (bringing the total to 14€) and was completely worth it IMHO. We saved quite a bit of time waiting in line. For an extra fee of 5€, you can select an option on the site that gives you a guided group tour in the Colosseum. We traveled without a larger tour group, so this guided tour gave some good historical overview, and it took ~45 minutes.

Afterwards, we went to the Forum/Palatine Hill complex. There are multiple entrances. The one that is closest to the Colosseum tends to have crazy lines (as it did when we were there). There is an entrance further south on Via di San Gregorio (map here) that had a much shorter line, which probably saved us 20 minutes.

Oh, and if you thought the crowds 30 years ago at the Vatican were bad, it's insane now. Also, the entrance to the Vatican Museums is different than it was 30 years ago. Anyway, that whole experience felt like a blur because of sheer number of people and things to see.

Well, over the last 40 years or so I a) lived in Rome (for work) for a total of ~15 months; b) visited (for work) about 30 times for a few days each; and c) have visited for "pure pleasure" about 10-15 times. Still, there are certain "things" I haven't been able to visit, which I'm always planning to do/get the "next time". I have a trip of the third kind (pleasure) planned for October and I'll get a few of those missing gems in. I'm never, ever getting enough of this city. :)

In my opinion, getting inside the Colosseum is not worth the wait/crowds. In that area I would rather concentrate on the forum and have a look at the nearby Basilica Dei Santi Cosma e Damiano (5th century), see the Roman Senate building, Capitoline museums, Basilica di Santa Maria in Aracoeli (Rome's titular church). Elsewhere, check out Trastevere for a stroll, a meal and some beautiful churches. You say that you have been to Vatican. What about the Lateran Palace and Basilica di San Giovanni in Laterano? It is hard to recommend without knowing your interests.

And I am definitely in agreement with KLouis - I don't see how one can see everything there is to see in Rome even in a year, let alone a couple of days

Rome airport (FCO) departure nightmares
 

Enjoy your trip. But FYI, getting through passport control <<departing>> FCO took an hour tonight (security took 5 minutes). Am told it's like that every day/night. They've got n row of shiny new passport readers that don't work. And of the 15 booths to check passports, 3 were open while approx 150 angry people waited, sans AC. Why it takes the Italians 5 minutes (average) to put a meaningless exit stamp on each passport is yet another mystery. Everywhere else in the world, this takes 10 seconds.

Excellent advise and tips from everyone! Thank you. I know it is corny and touristy but has anyone used the "hop on & hop off" bus to get around to the various sites?
As far as interests...I'd prefer not to spend time in a museum (and yes, the entire city is a museum!) but I do love architecture, ruins, fountains, cathedrals, and also love stuffing my face and sitting at a cafe people watching. One of the days is my birthday and I haven't decided whether to find a splurge restaurant or just eat pizza & gelato all day. I know I can't go wrong with either choice.
Tlvyyz, thanks for the heads up on the airport. I am really glad I switched my departure flight from 9am to 11am. It sounds like I will need the extra time.

From what I have heard/read, it is not worth it. My understanding is that because of ZTLs and such the buses can only access certain parts of the city. I've never done it myself, and maybe others have had more positive experiences.

I "did" the bus in the 90s (back then run by ATAC!) accompanying my sister who was visiting for a day or so. You get a rough idea of the "whole" city, that you can't get otherwise. I'd recommend this only to people who are there for a very short time.

Hmm...what are ZTL's? My concern is that I am going to spend (waste) a lot of time figuring out transportation from one area to another.

Well, that's me...short time!

ZTLs are restricted driving zones, basically limiting traffic in city centers to authorized vehicles including residents. What is mentioned above is an extension of that: trying to keep some of the historic areas including main squares around sights as pedestrian-only areas, so that not even buses can get there.

Then you have not yet been to Rome. I went to school there for a year, and since then I visit for a month or two, 3-4 times per year since the early 90's. There are still a vast number of treasures and sites that I haven't been able to, "get in." It's like saying I went to New York City for 3 days and, "got everything in," except Rome has about ten times more things to see and do.

In my first trip to Rome in 1979 (20 days, late September) we started walking from out hotel close to the Piazza del Popolo at around 8 am and we came back at arounf 7 pm for the aperitivo at a vineria on via Scrofa and then dinner. We repeated that a week later, visiting only places we hadn't seen the first time. The next timesI walked that much in Rome was on two of my recent visits a few years ago when I had to deal with an ATAC strike ;).

I am a walker so no problem with that. I was more concerned about time and getting lost (easy for me). I will see if the hotel can help me map something out that I can navigate on foot.
Is it difficult to locate taxi stands? I assume that you can't just hail a taxi from anywhere on the street (like NYC). Are hotels a good place to catch a cab if needed?