I'm having a similar problem with my 04.
Last Friday, it wouldn't start. Jumped it on Saturday. Got it going, drove it around, charged it, it started fine afterwards.
Sunday morning, no start.
Monday morning, jumped it. Drove it to the ski resort. Shut it down, it restarted fine. So, I disconnected the battery and let it sit for the the day. Reconnected the battery at the end of the day and it started great and ran fine.
Parked it overnight with the battery connected. Wouldn't start Tuesday morning.
On mine, I believe that I have a parasitic drain--something is still using electricity after it shuts off. I tried to test for it on Tuesday, but had problems with my tester (probably because it was as cold as I was). I will be doing more testing this weekend.
I think that it sounds like you also have a parasitic draw. The simple test would be to jump it (major hassle), drive it around a while (I drove mine about 40 minutes to the ski resort) until it is charged enough to start. Then park it. Disconnect the battery overnight and see if it still has a charge. If it does, then you have a draw. Now, you have to test and try and find the source of the problem. Google how to do the test (I'm still working on it, so I can't describe it all that well).
Or, just throw a 10mm socket and ratchet in your truck and disconnect the battery every time you park the truck -- that will be fun. Haven't suggested it to my wife yet...