If you are planning to leave the camper in full time, then forego the expensive professionally installed bedliner. It is good product and if you were remotly planning on doing contractor type work along with hauling the camper then I would say do this route.
But, consider doing a DIY liner such as Hercu-liner available at most auto parts stores. I installed this and then a thick rubber mat and it provides the right amount of added friction for which to install a camper above.
Sometimes the DIY bedliner gets a bad rap. My response to those nay-sayers is that most likely the instruction to install were not followed. Proper preparation is key to the DIY liner success. I installed it on both my trucks for TC hauling and minor home dept runs. If I were doing heavier duty work requiring bed use then the DIY in not the product. I think it would suit you well for the purpose stated.
I would definitely get rid of the plastic liner.
JMHO.