You can easily setup a “top rope” from the top of the vertical section with gear , there are also some anchor bolts not too far from the top of the vertical section but they aren’t directly in line with the crack, you have multiple options (bring a standard rack for top rope anchor and the belay anchor in the alcove, with extras in big cams) heavy in grey/silver BD #4 & old style purple BD #4.5 as well as new BD #5’s work great, bring extra of those and a couple #6’s, also a large hex(i.e. old school CMI chock, bong, or big bro that is the same size of around a BD#4.5/5) or piece of 2x4 wood the length of a BD#4.5/5 around slightly engaged/to barely tipped open works as well, to help as a rope drape re direct at the lip, so the rope doesn’t get sucked into the crack and rip your gear in at the lip when/if you fall off. The crux is the lip. So plan accordingly.
Rap to the lip and reverse aid the roof to setup directionals. Have your partner do the exact same reverse aid to get to the alcove safely/easily. Make sure the ropes aren’t crossed and they are running as straight as possible in the redirects before you and your partner start climbing the roof. (Be mindful of how the carabiner gates are oriented as one rope can easily clip into the carabiner and have both ropes running in that single carabiner, so be mindful of the gates facing away or use lockers on some redirects to mitigate this issue). In the sense of typical working a route by “top roping” is not the case with roofs usually, as it is with the Paisano overhang. If you come off anywhere past the first couple feet out of the alcove it’s really hard to get your feet back on the slab (unless you’re really tall haha) and reestablish into the roof, so basically once you start the roof, anywhere you fall, you will just be in space or may slam lower into the slab depending on rope stretch and the belay given. So have a plan and some ascenders/rope grabs and a pas/lanyard to get back up to the roof easier without rope shenanigans.
Other beta I recommend is bring some burly oversized gardening gloves and hand Jammies that fit over them, like Largo style (John long) with welder gloves & tape back in the day. Have fun & be safe!