upcoming family vacation

we are getting ready to go up north on our yearly vacation to ludington. we stay at these cute little cabin with my in-laws for a week. It is usually a total blast. this year my son is 18 months and now mobile. last year was pretty easy cause he wasnt yet crawling and couldnt get into everything. does anyone have some advise or tips on how i can survive this so called vacation without going crazy chasing him. i want to let him be a boy, get dirty, have fun but i also want to be able to relax a little myself.
my in laws kids are all a bit older and they pretty much do what they want and just go about their own way. so any baby proofing tips or actives would be helpful. thanks.