The good news about a diesel that uses a lot of oil is that if it starts and runs good you can keep driving it as long as you can carry enough oil with you to get where you're going.

In a gas engine this is not so. Once the engine starts using lots of oil, it will start fouling spark plugs and otherwise not run well.

The biggest down side is the hassle of keeping it full of oil, and the risk of letting it get low and spoiling the engine.

My advice is to keep it full of oil while researching and preparing for an engine overhaul. These engines rebuild well. If the pistons are okay upon inspection, you can replace the cylinder liners, lower bearings and do a valve job including guides and have it back like new.

Good luck,