I'll just cut to it. It has 198,000 miles on it. This will be my first big project with the Jeep. Have only done easy maintenance thus far (spark plugs, tires, brakes, shocks) the biggest project completed thus far was the radiator. I was then dealing with an annoying oil light that would come on at idle. I changed the pressure sensor, thinking that would be an easy fix, but the the light persisted. Then I started to get an intermittent high rev at idle. Which then turned into what is now a real performance problem. Everyone I've talked to suggests replacing the head gasket. Seems to be a lot of enthusiasts/ knowledgeable people on this site, so I figured I would see what yall thought.

 

Might want to start with the symptoms, and go from there.

 

IMHO Low oil pressure and an occasional high idle that progresses into a performance problem don't immediately condemn a head gasket.
Do you have oil and coolant mixing? Any overheating? Loss of coolant? Bubbles in the radiator? White/gray smoke out the tailpipe? Those are more typical head gasket problems.

The high idle is likely a vacuum leak or sticking IAC, perhaps a worn out TPS, the low oil pressure could be bearings or a worn oil pump.
Do you have access to a compression tester and coolant system pressure tester?

 

Radi is correct. Have you been losing coolant or adding coolant often? The year 2000 is the worst for head failure (cracking). This allows anti-freeze to mix with the oil which in turn wipes out the bearing which will show up as low oil pressure.