Here is something I have done in the past that worked. I put my basement dehumidifier in the closed vehicle and just let it run. You have to do it is increments because there is a lot of heat created by the dehumidification process, but the water you get in the tank is mostly from the moisture in the vehicle, though some percentage is from the outside. I once used too much water shampooing the carpets and used this technique - car was eventually bone dry. Give it a shot. If you start smelling mold, all bets are off. Best thing is to dismantle your truck, next best thing is to evaporate the moisture in it.