OK, to start: packaging pre-played families into houses = Very Bad Idea. Moving an occupied and pre-played house into the sim bin ends up ripping the character files as the sims' relationships to sims in other houses get severed. And borkination of all sorts ensues when these occupied pre-played houses are placed in a new hood. Do not do this if you want your new hood to survive longer than a month or two.
Do you have FT? Just use the new neighbourhood terrain elevation cheat/tool to flatten the hood. You may need to temporarily move families to the sim bin and make copies of their houses into the lots and houses bin (unoccupied!) so you can place everything back down again once you're done leveling. The cheat is modifyNeighborhoodTerrain [on/off] and you enter it in hood view and then use [= Raise, ]=lower, \=level, p=Smooth terrain
Hi SenkoTwiik,
Engram is correct about about the problems with trying to package lots with families. However, if you use the neighborhood terrain tool, then you can use the lot move tool to move a lot to another location while leveling the area which had been around it. I've done this successfully with no indications of problems (of course if anyone knows of reasons to not do this, let me know).
The problem is that the neighborhood terrain tool won't allow you to select terrain near or occupied by a lot (at least a lot with sims residing). Moving the lots away, modifying terrain and moving the lots back worked for me.
Thanks, simsplyr