IF he's used to a good routine and attached to his bed, maybe bringing the pack and play with the anti mosquito net would be a good idea for naps (you can place the pack and play in a not so loud spot and let him know this will be napping place). Stick to your routine as much as possible (one of my friends took to her camping trip an inflatable pool to do the baths
) and as soon as you get there, let him know where his sleeping will be (for nights and naps). Bring along favourite teddy bears or loveys and set his sleeping spot as similar as you can (I always bring sheets, pillow and teddies to ALL our trips... i even bring the ocean wonders LOL but that's because im a freak... you dont have to go that far). Once we get to our destiny, the first thing i do, before unpacking or even say hi to family, is setting up the sleeping spot, letting ds know that Teddy/Monkey/whoever came with us for holiday, and set up sheets and pillows, so he knows where he's sleeping and feels comfortable with that part being arranged. Then when it's nap/sleep time i do things as similar as i can (in comparison to home routine) and stay with him "pretending" to be asleep so he feels secure and certain that even if we're sleeping in a different place, im not abandoning him. It usually doesn't take me more than 10 mins for him to be out (usually he's worn out from running around and extra activities on holidays). The first time we did this, it took him a good half hour to settle but that was the only time. Talk to him in advanced of how the holidays are so fun, how the place is like and how exciting is to sleep somewhere else etc so he'll be looking forward to it and will know what to expect.
Good luck, and have a nice time!!!!!!