most hotels will offer complimentary cribs while youre staying with them. If not, bring a colapsable playpen and put your baby to sleep on it's floor. It's just like being in a crib, only lower down. I do this when baby sleeps at my mom's house. (Most collapsable playpens are pretty compact when folded up)

There are a lot of great travel beds out there. I highly recommend any peapod style bed- they have a netting to keep bugs out and can be used in or outdoors. They can also be used by bigger children, but I'm not sure what the max age requirement is. The bed folds up into a tiny round case, so it takes up minimal room.

http://www.kidco.com/main.taf?p=4,5

Well, we have one of those playpens that fold up. Didn't take up much room in the trunk at all and that's what we used when we traveled with DS. I still have to check airtravel, since we're taking him to Germany in December.

If using a hotel crib, please check it carefully! I have seen some pretty shody ones! Dateline did a story one time and went to 3 hotels, 2 cribs at each hotel so 6 cribs total and only 1 was safe!

I saw something that looked kind of like a box at Babies R Us as a travel bed. It folded down and could fit into a suitcase when traveling. Not something I would use for long, but fine with a 4.5 mo old

We usually just get a king bed and have our son sleep with us for the one night between destinations, if we were gone longer then we'd pack the pack n play. Even when he was in bed with us for several days, he went straight back to his bed, no problem. He knew it was a different environment and different rules applied.