Yeah, there are a so many catch 22s with stuff like this that it can be difficult to know where to start really.
One given is that it’s always good to know what you’re hoping to achieve from a campaign and in fact that’s probably one of the first questions a PR person will ask when you meet them. I’d split them into things that you would expect, and things you would really like to aim at, but know you may not end up getting.
As far as preparation goes - have your online stuff (social media, distribution channel for your tracks - AWAL/Distrokid for example are good, press photos) all sorted out. Make sure the songs are tight, and try and get at least a couple of shows booked for when you release it so there’s something more for the copy on the press release. Seems obvious, but, erm, we haven’t always done this!
As for releasing it…well it depends what you’re trying to achieve with it, but yeah if you’re looking at press and radio pluggers then leading with at least one single is probably wise. It’s not a prerequisite of having videos for all of them. On balance we prefer to, but I mean money only stretches so far and depends if you think the tracks really need them to stand up. You see fuck loads of bands premiering tracks on blogs with soundcloud links now purely cos nearly everyone is a band gets so fucked by the ££ thing and people just forego them, or put something very lo fi on youtube.