Jeep repair. Now what? Junk it or keep it?

1994 Jeep Grand Cherokee AT V8 4WD 210K mi

This jeep has had just about everything done to it: rebuilt trans about 5 years ago, new starter, new rear differential, new rad/hoses, just tuned up. I am currently in the process of doing a head gasket job on it, and installing a new water pump. The father in-law says I should get a "new" engine for it or just sell it for parts. I want to keep it, but dont know what to look for in terms of upkeep so I dont have too many more probs in the next few (1-2) years. I was told it wouldnt need an overhaul, but what next?