Stamina definitely goes. At over 430 and not super active, running is very hard and walking nonstop is too much in about 20 minutes.

Another thing, eat late at night, then sleep. Goes straight to fat.
Also, drink calories. Milkshakes or juice, both high in cals and sugar.

For gaining:
1.BK
2.Hardees
3.Sonic
4.Taco Bell (not for straight calories per item, but for number of items I can consume)
5.Wendy's

All of these are high calorie per dollar, and all but Bell have ice cream to really fill in the gaps in your stomach.

Just keep eating. Work on expanding stomach capacity. That will make you feel hungrier more often. Perhaps try starting off a day with a peanut butter sandwich. Very calorie dense, but, at least to me, not too filling.
Junk food is another obvious choice, but not too much, just more than you have before.

Yeah, a horizontal stripe polo shirt that's too small is basically the choice for worst look for me.

I'd like to add Culver's. Everybody above their teens is either a built farmhand, or a total fat ass ordering cheese curds and a double butter burger.

I would be nearly 650 pounds. If I could move at all, I'd definitely have to change where I sleep, because upstairs would not work.
Once I got somewhere safe, I'd probably just keep eating. No coming back from that much weight.

I really don't want to brag, but no.
When it's not erect, you can barely see it tho.

If they're on the fence, then they've thought about it, which is more than most.
I'd emphasize size, clothes and booths becoming tight, and socially, you'll find friends who understand being fat, if not gaining on purpose.
I started really eating to gain in college. There was an always open buffet near my room.
In a weird way, I felt I'd made the right choice when I became the fattest in my already hefty family.
I keep gaining because I'm still hungry.

Having friends fatter than you is good for gaining, but it becomes strange when you outgrow them. They give you a hand-me-down shirt, and it stops fitting.
You become the fatter friend, and your friends assume you need more to eat, so you become the fattest friend faster.