I have an esp that docblacky was kind enought to help me create(that alters the vanilla prices of carriages) but now id like to add the hearthfire houses to it but was wondering if someone could walk me threw the process..il give you credit for your work and dont mind sending you a copy of the esp to work from....thanks for any help in advance.

Don't the Hearthfire Houses already have a carriage? Or are you trying to change the prices charged for the trip?

http://www.uesp.net/wiki/Skyrim:Transport#Carriage

Yeah hearthfire has carriages what i want is to alter the vanilla carriages and make it so they can go to the 3 hearthfire homes once they have been purchased.

Wait, you can't take a carriage to the Hearthfire houses? Only from them? Weird....

Anyway, this mod adds them to the Hearthfire content, see how they did it and use those techniques in your mod

http://www.nexusmods.com/skyrim/mods/15508/?

I had trouble with that mod(so did other people) with it causing crashes later in the game.

Yes, but you can get an idea of how the part you want is done. This is a pretty large mod in scope, but that does not mean all the parts are borked. Anyway, once you see how the carriages were added in that mod, then you can mirror that for your mod.