I am in pretty much the same boat as you right down to the understanding wife and the aggrivated feeling that this thing is never going to get done. I am doing a frame swap to boot. So even as I go along I am running into stuff that don't quite work out according to Hoyle. I have been working on my 51 half ton for about 2 years now. Every year I say maybe I'll have it under primer by the next spring. It aint happened yet. I have done about every thing the other stovebolters have suggested and sometimes I still get really frustrated. I will say this though, going to a show and seeing a finished truck that someone else has done really gets me going more than anything else. Maybe our problems are similar. Up until about three days ago I hadn't worked on my truck much. I had gotten pretty aggravated with the drivers side door not wanting to line up correctly a couple months back, so I quit! I cleaned the garage up, put away all the tools and swept out the garage. I hadn't touched it until the other night. I couldn't sleep so I went out and started working on the truck and went at it hard for about three hours. That was three days ago. Now the cab, bed and front fenders are sitting on the frame, granted they are on blocks, but it is all there, and they are gonna have to come off because I have days more welding to do and fabricating for about everything between the core support, to the cab mounts, to the bed mounts and just about everthing in between. But....last night I welded in the motor mount perches and drilled, tapped, and mounted the motor. After I was done I cleaned the garage, put away most of the tools and swept the floor. When I was done ,I sit back at my radio bench and got the book out that I am using to keep records of my progress. I started looking at the pictures and once I seen just how far I had really come and how good it looked....man I was impressed! Truth is that none of the things I say or the other fellas have said may be the one thing that motivates YOU! But if your heart was into it when you brought that old truck home and started tearing it down, there will be some epiphany that will make you see that everything you have done no matter how little is progress even if it was a lesson learned.
My one suggestion that I haven't seen posted yet is if you haven't done it already, start keeping a log...I know it is just more work to add to the project, but hear me out. I started keeping a 3 ring binder with all my reciepts and notes and quite a few articles and posts from this site. I had taken pictures of the truck when I got it but really hadn't taken time to really document the project with photo's. Well, I didn't know that she had done it, but my wife had taken photos of about every step up until now, and about a month ago she printed them all out in succession give them to me to put in my binder. Once I got to looking through those pictures and actually SEEING progress I got a little more motivated. Now I almost enjoy working on the truck and putting it together to see how it looks, how it fits and how it is gonna look. I can actually SEE the PROGRESS and it has really got me going. I wish I wasn't on dial up here and I could upload the pictures for you all to see, that way I could show off and you may even see what I am talking about and it may help you find your motivation. My truck is far from being done. I probably won't see it done in the next couple years, but I realize now that it just takes time. I thought I was going to buy this old jalopy and get it going in a years time. It just aint gonna happen. Once I realized that it made a difference to. But seeing what progress I have actually made in those photos makes me realize the actual progress I have made. Now I can't wait to get out there and do something else and take a few pictures for her to download later. It is her way of helping me without being there with a wrench in her hands. And it is working pretty good so far. Now I bring her the camera to download the pics to the computer and she says "Wow...looks like you got a lot done today" and that helps too!
Whatever your motivation is it'll come!
Sorry for the EXTREMELY long post folks....but I can relate and had to spill my guts...kinda maybe even got carried away.
Good luck with your truck man... I gotta go get to work on mine!