I drive an 86 Accord with nearly 260,000 miles. Recently and without really any warning, the car became considerably difficult to put into or out of gear. There isn't any grinding gears, though there is a slight popping sound when the stick does go into and/or out of gear.

My first thought was that it was the clutch, because I had an issue before with the clutch cable becoming misaligned such that the clutch wouldn't disengage completely when fully pressed. The lack of any grinding noises or forward motion with the clutch pedal fully depressed makes me think this isn't the problem.

Honestly I'm not very well knowlegeable about cars, and I would much appreciate any advice I can get.

 

sounds like your clutch cable may be out of alignment. Have that checked out and you may want to change your transmission oil too. (Use honda manual transmission fluid)

 

A common sign of a clutch going bad is difficulty going in to gears. Reverse is probably the best indicator.
Cruising on the highway in 5th gear, hold the gas pedal steady and then bump the clutch pedal. The clutch should re-engage quickly, if it slips it needs replaced.
I'd also agree to be sure you have the right fluid in the trans. If the trans somehow got 80w90 put into it there will be problems.