I've always shared this, in my guide for broforce.

I dont have the level file itself on hand, buuuut:

Here is the tool https://drive.google.com/drive/folders/0B6haS_TovWoqV2l3S3piWWJvUkk

Basicly it allows you to select previously built landscapes, and "convert" them into spawnBlock triggers. You just need to then load the newly generated level file and delete the old blocks and setup an trigger for your spawnblocks.

i cant seem to save this locally, is there a separate bfc link?

Lil update here, background support might be possible but only with huge amount of extra triggers, have to performance test it eventually

I wont do background support as they never connect, also no doodads, as they obviously arent terrain^^ (mooks and and two unplaceable blocks are spawnable though). Until i update you can look at this picture i used to create the hashtable (i simply spawned in all blocks from left to right, 4 each)
http://cloud-4.steamusercontent.com/ugc/527257229458144250/84A99499BCAA1509448C7D3C31CF37768E08B7CF/2048x406.resizedimage
As for the gabs, i believe them to be misc stuff like terrain rotators, but its hard to figure out, so no support for those yet (i dont think they would work anyway, as terrain rotators usually need a level reload)

Yes they can, also the bugs with background and connection are irrelevant on them as they only have one way of spawing.
Gonna update my tool tomorrow if i find the time. Wanna fix a bug from the current public build first

Can ladders be spawned? That would be great for making shortcuts.