If you are tempted by the RAF, hire a knowledgeable RAF guy to help you inspect it. If Dwayne Hunn is still around (he was in Texas) He knows RAFs and travelled in the past to do this service. There are probably others but, your location might dictate who would be the closest.
The RAF had a history of bunt over accidents. Most of these were caused by the factory refusing to accept the fact that they needed, and still do, a large horizontal stabilizer. Putting a large stab on changes them from a tiger to a house cat. Disclaimer: I haven’t flown one with the little wing like trim feature invented by Dwayne. Having said that you still need to learn rotor management, ground handling and all things associated with fight. You will either kill yourself or severely damage your gyro and person if you don’t take lessons.
As for your question on purchasing to just do ground operations. Don’t do it. You need to learn how to do ground operations or you could total the gyro on the first blade spin up. Once you attach the blades the temptation is too great to do something beyond your experience.
I totally agree with Vance on the topic of inspecting a gyro. The only safe way to buy and fly the RAF would be to disassemble and inspect. You will need to change every hose and belt as well as (maybe, maybe not) the fuel pumps. All pivot points need disassembled, inspected and lubricated. Although most rotor head bearing seem to last forever, a new one is less than 100 bucks, cheap insurance. RAF had a rodend service bulletin. The original rodends proved to be to small. Jim Logan had one break while taking off with a student. Jim Mayfield found one ready to break during a preflight. Make sure it has the upgraded rodends.
The first RAFs came with the EA-82. It was the overhead cam version of the 81. It didn’t have enough power for the size of pilots today. (Although Dan H flew the heck out of his) The cabin was also smaller than the revised versions.
The one you’re describing sounds like the EJ-22 powered RAF. They perform very well and have the larger cabin. The carb’d engine was bulletproof. After the EJ-22 they used the EJ-25. (Someone correct me if I’m wrong) The 25 had issues with the fuel injection. I believe they got the problem solved. My buddy Gary returned his 25 to a carb for reliability.
I like RAFs with stabs. They are a good two place and well priced in today’s market. (The stab does give the gyro a lighter nose so new cheek plates will likely need made. The stab also gives some cabin hop) anyway, good luck in your quest.