I zip tied down the seat sensor on mine
L3200, so I can stand or jump off without it dying. As you probably noticed the HST acts like a brake when not being driven. I'll jump off mine on a hill in M range & it will roll a foot or so a minute. Not great, but good.
The Parking brake is a little lever on the right side, just to the left of the brakes. You jam on the left brake (or both if pinned) Then pull the parking lever to hold the brake in place. A bit annoying, but workable. I often drop my box blade instead. You get use to the twitch to the left when you try to take off with the parking brake on. I never pin my brakes unless someboyd else is going to drive the tractor. With the HST I use them for turning & very occasionally when trying to do precision pickups or drops on a hill.
Whatever you do, get the tires loaded & always use proper ballast, especially given your plans to mostly use the loader. Loaded rear tires really help with the traction & help keep the rear on the ground when lifting things. However loaded tires don't help keep the load off the weak front axle. Proper ballast on the back unloads weight off the weak & complex front axle to put it on the strong & simple rear
At one point I was trying to put a 100, maybe 180 tops gate on the pallet forks. It was just a gate, so I didn't bother with putting anything on the back for ballast. It was also only in 2wd & on a slight downhill slope (front wheels were maybe 6-8" lower than the front). I let off the go pedal & kept going. Jammed on brakes, no affect. FInally ended up with a couple small holes in the sheet metal in the back of my shop.
Moral of the story is, always ballast properly (not just load the tires) & use 4wd if you pick up anything with the loader as the brakes are only on the rear (and don't work in 2wd if your rear is light). Your brakes are also not likely to work if the HST doesn't stop you when you let off to go pedal.
I'd still highly recomend the tractor, but just be aware of the limitations & proper operation.
I got R4s as they have a higher load capacity, are a bit more durable. They probably have a little less traction than R1s, but I haven't had any problems, I'm power limited a lot of the time.
You'd be crazy not to get the loader with the SSQA on it rather than just the pin on one. Swapping between bucket, pallet forks & a grapple just takes seconds with the SSQA. Could take ages with a pin on.