BILL - A #104, 124, 106, 126, 86, 108,or 128 will have continuous foot rests back to the fenders. There's others too, the GD versions of the Quiet lines, the 800, 1000 & 1200, also the GD versions of the red tractors, think they're the 482, 582, & 582 SPECIAL. The round fender tractors, CCO, 70/100/71/72/73 all have gaps between the foot rests & fenders.
The gear drive rearend isn't exactly like the Cub Farmall but they share the same beefy design and many parts interchange. The CUB rearend doesn't use a reduction housing on the front of the transmission, the transmission runs at engine speed, 1400 to 1800 RPM depending on vintage. The final reduction is via bull gear & pinion at the ends of each rear axle carrier to slow RPM to the large diameter rear wheels. The CC version uses a 7:1 reduction unit so all of them run 515 RPM in the transmission, and the axles directly drive the rear wheels from the differential. I'm sure KRIAG can post a pic of a CC rearend suspended above a CUB tractor to show the differences. An Internal brake rearend would be the simplest and most common GD. They have an internal 4-1/2" oil bath wet disc brake that works thru the differential to give both rear wheels braking effort. They're really reliable and effective. The clutch is a 4-1/2" dry disk clutch that is very durable also. For just mowing & general yard work they last almost forever.
I found with My SON when he was 8-10 yrs old got along better with a "hydro", he didn't get the gears completely engaged when putting the Cubbie in gear.
Depending on the model & HP of the GD Cub you can use either a 38", 42", or 48" deck. The 38" & 42" are common, the 48" are "Rare", (no SILLY COMMENTS GUYS!) If the blades are sharp, the baffles intact, the deck leveled properly, and the grass is dry they do a good job mowing. Maybe not as good as a Simplicity deck but close. Decks in good shape are around. Depends how they were maintained, afterall, some of them are 40+ yrs old.
I would say most guys here have their CC's as "Daily Drivers", some have newer tractors to mow with but most don't. I haven't run my 70 since between Christmas & New Years, it might give me a problem starting, the main fuel valve in the carb sticks closed. Last time I ran the 72 was DEC 13th. when I finished aerating the yard. It will start right up on the 2nd or 3rd revolution next time I get on it. The 982 would need to be cranked a bit to get gas up to the carb but would start after cranking 2-3 times for 5-10 seconds each time.
Like I always tell everybody, I'd consider buying a new CC or ???? if I ever wore my old 72 out, but I've been trying with NO success for 31 years so I keep running it. It's a '68 vintage, so 44 yrs old this spring. It's the tractor ALL my attachments were designed to fit and work on. It would be the LAST tractor I'd ever think of parting with.