@redeven Yes you can do that but it doesnt work the way you implemented it.

build,harvest and such are only shedules if the current gamestate allows ist. (when you are in range).

Your second command will always return ERR_NOT_IN_RANGE. Meaning it wont be shedules to be executed after your script is finished. I Testet it with one of my harvesters. While approaching the source it never Returned 0 (OK) and it wasnt executed when the harvester was at the source.

it only works the other way around.

For example:

youre in range of your transfertarget. you sucessfully shedule a transfer (retVal == OK). Then you can issue a move to somewhere.

The only thing that you can change while your script is running is memory. Everything else stays the same until next tick. And all commands must have the prerequisites fulfilled when they are issued and dont consider the next tick.

room.find, creep.pos.findclosest, and so one all work in only one room. creep.room returns the room the creep is in.
Unless you move a creep out of the current room all your role scrips should work in the room the creep is in. If they are in similar style to the tutorial scripts.

If you claim another room and have a spawn there you only need to setup autospawning for that spawn and you should be done.
Your autospawning should use room specific data. Just iterating over Game.creeps to count builders and such doesnt do the job. Since Game.creeps has all your creeps. You have to filter on the room you want to spawn for.

Dont use roomnames or IDs in static code. Like the old poster did. Your code will be useless if you need to respawn for example.

Im fairly new too.

Im fan of Multirole creeps that use renewing. When the primary Role cant be fulfilled they automatically switch to do something other. When theyre big enough the harvesters will mine our the sources fast and then switch to building repairing or upgrading until sources are available again.

I use as many harvesters as the sources have spots to harvest.

On sources far away its probably useful to use haulers and containers or some more harvesters than the source can take. (beware of pathing though. if its too tight default pathing can lock multiple cpreeps in place)

When there is storage available ill probably introduce a Hauler that hauls from containers to towers,spawn and storage (in that order) and if containers are empty towers and spawn are filled from storage.

One Primary builder,repairer and upgrader so those task wont get neglected that take their energy from containers, and storage. (spawn energy is only used to spawn and renew creeps)