So, this "25 for 25" challenge has been intriguing me for the last few weeks. I fly JetBlue often transcon (family in CA), and have held Mosaic before. I don't expect M1 status to increase in value

, but having its perks for 25 years (or until JetBlue merges with someone) is attractive enough to me that I wanted to see if it was practicable to qualify at a reasonable cost. Unfortunately, I don't have a JetBlue-branded credit card, and based on Barclays' lackadaisical customer service I wouldn't get one in time to make a meaningful difference. Opportunity missed; oh, well.
I had a free week coming up, so I messed around setting up as efficient an itinerary as I could, within the constraints of JB's route map. Being BOS-based was a huge benefit, of course. After constructing a grid of all JB's flight connections and messing around with Google Flights for a few hours, I made a command decision to stick solely to domestic flights. I have had some experience of Caribbean immigration lines and felt that was a great way to blow an otherwise easy connection. Also, my research showed that attractive inbound fares to foreign destinations often correspond to brutal outbound ones (exit tax, perhaps?). However, I did include SJU and STX, as they're US territory.
Similarly, I avoided any transcontinental flights. As others here have noted, JetBlue's route is heavy on north-south East Coast, with some cross-country routes which regrettably only connect via East Coast cities. The only interesting options for an efficient circle itinerary were SFO (which connects to FLL, JFK and BOS) and LAX (which connects to these as well as PBI, EWR and BUF, of all places). The rest only fly to BOS and/or JFK. For maximum efficiency in minimum time, I stuck to mostly East Coast routes; the exceptions were AUS and TVC, which have easy same-day returns from BOS (cheap, too, as it turned out). The final result was a sort of North-South cross-stitch linking the busy FL hubs with various Northeast destinations, some of which had precious few connecting flights.
I wound up with what I think is a pretty good itinerary, hitting 15 distinct destinations in 5 days (plus an evening positioning flight to MIA). Many of the flights couldn't be booked together on JetBlue's website, because the arrival and departure were too close. That (unsurprisingly) was because the same equipment was being used for the incoming and outgoing flights. No problem: I split itineraries at those stops, since it's hard to "miss" the outbound plane if I'm riding in it inbound (OK, mechanical problems happen, but you see my point). This logic applies to lots and lots of one-way flights originating in BOS, JFK and the southern JetBlue hubs.
Then, two days ago JetBlue dropped their "Summerize" sale. I promptly revisited the whole itinerary, did some rebooking at substantially lower prices (yay), redesigned a couple of legs, and added a long weekend in August and two distinct roundtrips from BOS. I now have all 25 distinct destinations booked at an per-destination cost of about $168 (including revisited destinations and seat upgrades, but not including five hotel nights and one rental car). All the hotels but one have free airport shuttles; I splurged at MCO and booked the in-airport Hyatt Regency, since I'm landing at nearly midnight and leaving just before 9 AM.
As part of this, I tried to build in some resiliency to the itinerary. Apart from the same-equipment destinations, there is only one close connection, and it's 61 minutes. My norm is to skip any extra-cost seats, but in this case I decided to pay for row 2 in the inbound flight as insurance. I don't plan to check in for any itineraries until I've arrived at their origin airport; if weather or other factors mess me up, I'll cancel to my mileage bank, lick my wounds, and rebook.
I start next Tuesday. With a little help from above, I will have 16 destinations nailed by the end of that week. I plan to bag six more in a four-day stretch in late August (thanks to that unspeakably well-timed sale), and I have three more scheduled as inexpensive single-day round trips out of BOS. If all goes well, I will visit all 25 destinations by September 13 at a total flying cost of about $4194 (all in Blue class). If not, I still have two and a half months to finish the job.
Destination list:
MIA, SJU, STX, (SJU), TPA <stay>
EWR, FLL, BOS <home>
DCA, MVY, JFK, MCO <stay>
HPN, ACK, (BOS), PBI <stay>
BDL <rental to (JFK)>, RSW <stay>
(BOS) <home>
<break>
ILM r/t
<break>
AVL r/t
<break>
BNA, (BOS) <home>
(MHT-JFK), ROC, MHT <home>
AUS, (BOS) <home>
TVC, (BOS), PHL, (BOS) <home>
<break>
MKE r/t
My layover time is necessarily limited in most of these, but I will be trying to pick up something at each airport to commemorate this run. Any tips, places to quickly get something healthy to eat between flights, cool airport lore/offerings, etc. will be appreciated; please PM me. Likewise if you're doing the run yourself; it's not inconceivable that we might meet en route.
Wish me luck. I'll keep you posted.