If your flying make sure you get up and walk for abit especially if you've got a sore back because it gets worse.. I went on holiday when I was 25wks and fine fly in out but coming back it was so uncomfortable on my back so would adviser a little pillow for it x
You should be fine, if you plan on being out of town for a while I would ask your provider for copies of your pregnancy records just in case. Most will just tell you that they can always fax paperwork over if needed to any L&D.
From what my midwife says, its perfectly safe if everything is going well. If you are going to be sitting still for very long, definitely make sure you wear compression hose and take a stretch/walk break as often as you can...don't want any blood clots :) I'm 25+5 and my sister is getting married on the 10th so I'll be strutting my compression hose for our 6h drive too :)