On quite a few of the city plans, Clean and simple will work, it just needs a little help to backfill on the gaps where terrain was nudged or buildings were changed.
Probably not going to work in Sanctuary or Murkwater, but likely to work just fine at Abernathy as long as the terrain didn't get changed overly much.
the clean and simple series does flatten the terrain quite a bit. this makes it awesome for plot planning using sim settlements but probably not so compatible with city plans. the good part though is with the completed all in one mod you can choose which settlements to install and which to exclude so you can still use city plans on those settlements which you really like the plans for. just a little trial and error involved i suppose.
jenncave did a great job modifying all the vanilla settlements to make them cleaner and easy to build on. cant say enough good stuff about this mod. she recently completed all the vanilla settlements and put it in a single installer. highly recommend any sim settlement junkies try it out. link below... welll... nevermind cant post link but just hit the nexus for Clean and Simple - Settlement Startup