Though I think you will thank yourself in the end for taking the Raptor on the long trip (for comfort sake), I don't think driving a HMMWV is unfeasible. I would consider it the same as having any old truck (speaking specifically from my 20 year old DD), stuff will break and parts are going to fail because of their age. But if I drive it often enough, work on it often enough (more than enough), and become familiar with the truck through interaction, I wouldn't hesitate to drive it from coast to coast tomorrow.
If you service your truck, are familiar how to trouble shoot in the TM, and carry some basic tools (other than unforeseen catastrophic failure) then doing HMMWV road trips should be fun. I also believe that some of the problems that all Green Machines have is how long they sit and don't get driven. Putting on some road miles a couple days a week should be the first step. Now, I just need to find enough days in a week to drive everything...
