Originally Posted by RumPatrol

Do not do this. It is not worth it right now. Just go to the SkyClub. There is no way to walk between the terminals right now, at least there wasn't the last few times I was there in the last couple months. Even if there was, it isn't a direct walk. The construction is an absolute disaster zone and the shuttle buses may or may not be on time and may or may not take half an hour to get you over there. Last time I was at LGA I was meeting family arriving at B after I arrived at D, it took 45 minutes to get to B arriving around 4pm.

B to C should be much quicker, when we did the reverse departing LGA and I dropped family at B before leaving from C, it took about 20 minutes to get from B to C. Around 3pm. In my opinion, that Centurion is just not worth the effort right now. I'd argue that there are very few airport lounges in the world worth that effort, but I'd also argue there are very few airports as incompetently designed as LGA. If you do want to do this and have enough time to enjoy it, I'd plan to arrive at the airport at least 3 hours early and then plan at least half an hour to get from the lounge to C. If it goes fast, you can always go to the SkyClub for a bit before your flight and grab another drink.