In reply to imkevinmc:
If budget is no issue then look at Assos. DHB are highly rated for mid price range. Most decent brands make very good shorts, Castelli, Santini, Rapha etc etc. As others have said find what works well before your trip. Someone somewhere will tell you Aldi £20 shorts are great - ignore them. They're great for £20 but not comparable to 'proper' shorts
If you are able to wash and dry them every night then you may get away with one pair. If you are camping/bivying and this isn't possible then take 2 pairs and dry the washed pair by strapping to your seatbag/pannier during the day.
If you wear one pair continuously the pad will be a mess of nasty bacteria that will lead to saddle sores and general nastiness where you don't want it.
Some people swear by Chamois cream - again try before your trip. I'll use it if I know I can shower every night but I'll go really easy with it as a few days with no shower it can end up a bit unpleasant.
I've found Climb On creme to be good on saddle sores if they do appear.
Bike fit and saddle type and position are probably more important and the most expensive shorts won't help if you're in a bad position on your bike all day.