http://www.webastoshowroom.com/images/truck_trifold.pdf
These work.... They use them on the Dalton..
A tank heater should fix your problem, you just have to work out the connection, MOST engines don't have block drains... The heater hoses should actually work fine as usually they are on opposite sides of the thermostat so they do push water through the block.
There are special fittings that replace a freeze plug on the block, fairly easy to install.
Or if you search almost all blocks or heads have threaded plugs for manufacturing/cleaning purposes.
Good Luck
Dave