Wow, that runs pretty well! It sounded like you were a bit concerned when you first picked it up whether it would run at all, let alone drive. Congrats on a great find! Can't wait to see it when you're done if you're going to restore it. Looks like you do have a couple of rust holes on it to patch up unfortunately...
This looks kind of like a newer version of the little rider that you have, Bolens 1000, the Green Brier? Can you tell us a bit more about these two? Was the Green Brier the first small riding mower Bolens made in the late 1950's to early 1960's and the suburban mower here was made in the late 1960's-1970's? They are pretty neat little riding mowers and it's good to see them up and running again!
The Green Brier is about 6-8 years older than this Suburban Model. Bolens had quite a few of these small riding mowers in the 50's. These Suburbans made in the 60's are probably the most common of the riding mowers and there seem to be quite a few of these around (Not really rare). They made these particular Suburbans from 66'-69' then they stopped making them as I'm guessing the small frame Bolens kind of took their place as the next "little mower".
I believe this one pictured below was one of the first ones they made. Maybe one of these days I will find one.......