Jaime~
Sounds like you've gotten some great advice. As far as the meals go, I'm not sure how far along you are with solids, but we actually found that eating out when dd was old enough to do a few finger foods got really easy. We timed meals (whenever possible) to be between naps so she wasn't tired and just brought along whatever finger foods she liked at that point--cheerios, small peices of banana--once we ordered a plate of avocado slices at a mexican restaurant (and dd ate the entire thing!!!! It was easily a couple large avocados
)--I guess if your LO isn't as into food, it may not help a whole lot, but for dd, she was pretty content for a good 45 min. to be working on her food. We'd also take her to walk around the rest. and look at things before our food came to the table so she wasn't already bored of sitting by the time we wanted to be able to eat.
The hotel thing--well, that's always been a bit of a struggle for us because we can't usually afford a suite or 2 rooms, so yes, someone gets stuck either going to bed really early or at least sitting in the bathroom or something reading. Honestly, I was always so tired that I usually volunteered to stay in the room and let dh go do something if he wanted (usually we were with his family if we were at a hotel).
Also, not sure where you are traveling from, but if there is a time change, you might get that to work in your favor. We went on a cruise when dd was 5 months and traveling from CA to FL, we got a 3 hour time change so we just tried to keep dd on CA time, which meant her bedtime was at 9:30 FL time instead of 6:30--that helped a lot with the evenings (it also helped that she was pretty happy to sleep in the Baby Bjorn, not so much in her stroller). However, she was not a good sleeper in general, and I think I would have traded vacation troubles for every night troubles
Good luck and try to have fun. Like pp said, you can always just fix it. Its hard to have an overtired baby, but sometimes family things are worth it (FWIW though, I wouldn't go to the birthday party either--that is just too late, and parties tend to be too much stimulation anyway!!!)
~Kim