I would definitely raise the camper. You don't necessarily need to get the tires "off the ground", but take the weight off.
Big bonus to doing this is a stable, firm camper! Virtually all campers I see at camp grounds that are there for the season are on wood or cinder blocks. I think it is just nice to not have a creaky, rocking camper for the season.
You are talking at least two years. It really will be only what... one weekend to set up? (maybe two weekends to get parts you forgot) Put the camper on blocks, get some hard plastic piping for your septic, and life will just be wonderful!
