First, the dollars lost to date are completely irrelevant (to this decision). The only reason to look at dollars lost is in the context of making future decisions. This is a trap that many people fall in to.
Based on the info provided, it is obvious that you should sell the truck. Step 1. Sell the truck. I'll be honest, I am selling a truck too. I really like it - diesel, sounds great, gets great fuel economy loaded or not, can tow anything I want. But I can do 95% of what I do without a truck and the other 5% I can use a small trailer (which I have) or rent / borrow. It costs me about $300/mo and just sits there most of the time. It can be someone elses liability. Anyway, you may think about trading yours in. I highly doubt that you will get book, even at trade in, and you will get hit again because the car you are buying can likely be bought less privately. BUT it doesn't hurt to hit up a few dealers or use Autotrader to get a trade in value.
OK, obviously you are going to want to replace it. Of course, the most MMM solution is bike, zipcar, etc. Assuming that is not possible or is simply too big of a jump, it sounds like next step is to shop. Again, would look privately. eBay, Craigslist, etc. MMM has several posts on MMM cars. I don't really care for the extreme end - early 90's Metros, CRZ's, etc., but there are many early 2000's cars that are cheap and reliable. Hyundais, Hondas, Toyotas. I like Nissan Sentras, Ford Focuses in particular but many options here. I've even seen cars up to about 2010 with higher miles for under 10k. Don't shy away from these. Highway miles (steady state operation, fewer warm up / cool down cycles) are much easier on cars that equivalent city miles. Plus cars today, in my mind, are 200k mile capable, minimum. Might be a good way to get a newer looking / feeling car for cheaper - and you aren't putting many miles on it so having 100k of life left is sort of useless.
Let's say you still want a truck though. OK, I understand it, sometimes getting MMM takes time (I'm not even half way there). How about a Ranger? 4 cyl / 5 speed gets mid to upper 20's. You can get 90's models with 4x4 even, but they are pretty slow. Colorado's are newer, more room, and the 4 cylinder models get decent mileage, 20's, even in 4x4. Again, not MMM but getting there.