You can tent your boat in plastic and leave a humidifer running under the tent. I've done that with green wood and it dries it out nicely. The same would work with your boat if you left the port covers off. Its a kinder, gentler way of drying out the boat.
I'd be careful of pumping heat into your boat without a thermocouple and a thermostat on the heat source. You could cause a fire if you left it unattended overnight. Heat lamps, hair dryers, electic heaters can all get hot enough to delam your hull. I wouldnt risk it a thermostat to turn off the heat source.
If you want to weigh your boat take the car, trailor and boat to the local dump, they have a drive on scale, give the attendant a couple bucks and he'll weigh you. Take the boat off and repeat. Subtract total from boat less weight and you have your boat weight.
Bill