The bus is out side security at the arrivals/baggage claim area.
It is a Blue & White (free) Massport Bus.
Be sure you get one that is marked Terminal C or All Terminals.
One of the Buses is marked Terminals A, B, Subway (do not take that one). You can always jump on a Hertz/Avis bus.
It is a long walk from A to C and it is not straight.
As u do not have to wait for DL luggage, you should have no issue if u arrive on time. U will have to clear security when u arrive at C.
Not 100% sure DL will give u your cape air boarding pass, but the lines at C for Cape air check in are usually short.

Checked luggage can be checked through to Cape Air. As for carry on luggage, just about everything goes in the hold on Cape Air Cessna 402s.

IMO:

Seat to waiting for bus: 15 mins
Waiting for bus: 25 mins
Bus ride: 10 mins

Massport's bus system is absolutely horrendous. They just need to be more frequent.

Thank you all for the help! I think I will give it a shot and if I miss the connection an afternoon and evening in Boston isn't the worst thing in the world :D

How did you do? I have a 45 minute connection from Continental (Terminal A) to Cape Air next week,..... I now have a feeling I won't make it, even with carry on.

The bus usually isn't that bad. But you could also walk from A to C, and that's about 20 minutes, maybe 15 on a good day, depending on how heavy your backpack is.

Also, it depends what gate you get in to in A, as the satellite gates where you have to walk through the tunnel easily add 5-10 mins.

That could be dicey. CO at least uses the main terminal in A, so you should be at the curb within 5 minutes of arrival. Still, a minimum of 10 minutes to get to C if the bus gets there quickly (maybe 15 minutes to walk) and you still need to reclear TSA over in Terminal C.

I'd say you've got misconnect written all over that one.

Not sure how you made your booking, but if you did it on one PNR through Expedia or some similar site, it often doesn't show all of the 9K flights BOS-MVY as routings, so a mis-connect may not be that bad. They usually have them nearly every hour until 9pm or so (check flycapeair.com). It's been a while, but the last time I flew 9K, they were very happy to switch my ticket to another flight later the same day for no fee.

Also note that DL and B6 are both running seasonal JFK-MVY this year.

Yeah, I am leaning toward misconnect too. Coming into EWR from LHR at 12pm, then 2:40pm to BOS, arrive in BOS at 4pm, all on CO. Then 9K to PVC at 4:46pm.

The 9K flight is a seperate PNR, but I am wondering if CO can check me in at EWR or even in LHR?

Seeing that I am in seat 1A coming in BOS, I can sprint for the Terminal A doors and then grab whatever bus (maybe a rental car bus) to Terminal C? I have carry on luggage.

Any other opinions considering this information?

Also alternative is I grab the 1:32 CO flight from EWR to BOS, but I could not book on same PNR coming from London due to connection time restrictions. This is probably an alternative, don't really care if I am not in First for it.

25 minute layover in BOS?
 

Was looking at routes from UIO to DTW and found a very reasonable flight with two stops (ATL & BOS). Although my layover in BOS is only 25 minutes! Is it even possible to make that connection??

Domestic-to-domestic in Boston on DL in 25 minutes is doable but very very little room for error.

Most likely, your flight from ATL will come into the satellite and your flight to DTW will also go out of the satellite. In that case, you'll be fine, but tight as Yahtzee says. If you happen to come into or go out of the main building, prepare to run. And if anything goes sideways, you're SOL.

DL requires you to be at the xBOS gate no later than T-15. If the flight is at risk of oversell, off you go and DL gets to fill your seat. This gives you 10 minutes from brakes locked on the inbound to the gate reader on the outbound.

Ask yourself if that is sensible in light of whatever it is you have planned at DTW when you get there.

More like no room for error. If the BOS-DTW flight is the last of the day, I wouldn't take the chance. Question is: what's the fare difference between a single connect in ATL and a double connect in ATL and BOS?