Yeah, I don't think buildings are really ideal for jumping, personally, unless you already have access to one because it's your workplace or residence. I'm speaking purely on conjecture here, but most roof access would probably be locked and only accessible to maintenance personnel. And you would also have to worry about hallway cameras - if security sees some random person come off the street and start nosing around, they're probably going to come after you, or call the cops, or both, and that might be tough to explain your way out of.
Personally, I would be looking more into structures like bridges or cliffs. I would also consider scaling something like a water tower, cell phone tower, or the like; tall structures that have exterior ladders for maintenance workers and aren't likely to have security on site. I would also favor a railroad bridge over a vehicular one, it would be less visible and more private.
But if I was jumping, I'd plan on investing in a pair of bolt cutters (at least 18", bigger is better especially if you don't have a lot of upper body strength) to cut off padlocks, because you're likely to run into them. Chain is normally easier to cut through than the padlock itself.
And most importantly; I wouldn't piss around when I got up there. I would work on the assumption that someone has seen me and called the cops as soon as I started climbing, so I might have as little as 10-15 minutes to work with depending on the response time in the area I'm in before law enforcement starts showing up. As the saying goes; shit or get off the pot. If I got time the top and found out that I had less resolve to jump than I thought I had, I would climb back down immediately and get clear of the area. I might also take a selfie or a video while I was up there so I would have an alibi if anyone managed to track me down and start asking questions about what I was doing; a slap on the wrist for trespassing is far better than an involuntary psychiatric hold.
