I don't remember... it's been years, but they used to be totally separate (in the 1970's). Perhaps you can go to Logan's website and find maps/info? Good luck.
If I remember correctly, they are not connected. I try not to fly out of there. Just too busy/crazy for me. Plus, you don't want to have to keep going thru security.
I remember the walkway being outside security. I double checked with the maps on the website and it appears that they are in the unsecured area. Plenty of places to eat in terminal C though.
Leave yourself plenty of time! Flew JetBlue to Aruba last week and it took 1/2 hour to check our bags in and 1 hr to get through security. We usually fly Delta and have never waited that long in a security line before.