Hate to say it but there's only one way to do the job right and it sounds like you know what that is.
The Kilz wont do anything to stop water intrusion and that goes double for Thompsons (Worst product of it's type avail). By trying to make stop-gap repairs, your just wasting money on stuff you'll have to tear off later or worse, spending money on stuff that's going to allow severe damage to the rig.
If you can't fix it correctly now, cover it with a good tarp and keep it dry until you can.
Sorry I can't give you better news.
Scott
