I explained that several times on several forums

And not so long ago on Daltaí
http://www.daltai.com/index.php/forums/viewcategory/1/chuig > to go to an event
chun > when the name of the place has an article
go > when the name of the place has no article
go dtí > same as "chun", however, normally in Ulster you use "chun" in this case, and there "go dtí" means "until/as far as" and is mostly used when talking about time (ceathrú go dtí a sé...).
eg.
A ghabháil chuig cruinniú
A ghabháil chun an toí
A ghabháil go Baile Átha Cliath
A ghabháil go dtí an doras (as far as the door, and then you stop before it --- in Ulster)