Interesting parallels in our lives,

I have a similar all weather construction site job in Maryland (Liberal Hell) and until I sold it to buy a Ramcharger I alternated between a 99 WJ and Ram 1500 4X4. My WJ was a 4.7 with 185K miles with a 2" lift and JK Rubicon wheels & tires. For my job of carrying myself and some equipment to pretty much anywhere the WJ was actually a bit better than my pickup due to the smaller size. Capability wise the WJ with BFG Muds & quadra-drive would go really sloppy places much more confidently my pickup with similar tires. I found maintenance cost was a bit more than the truck and mileage for me was not that much better at around 13 with the Ram and maybe 15 with the Jeep. The WJ did lose a mile or two per gallon when I switched to the heavy BFG muds. If you like your truck and want to keep it decent I'd fix the jeep and save the wear & tear. Sure a 2K investment seems pretty big to save a couple of MPG but once your truck is worn out it'll be way more than 2K to replace.