We would like to merge two of our servers together and in order to do that we would need to install SVN on the \"new\" server and then move over all of our repositories that we
If the new server uses the same operating system you can just copy the entire repository folder to the new server. No need to dump and reload it.
The relocate command allows you to point your working copy to the new server i.e. it does not help you to move the repository, it just saves you from doing a fresh checkout.
Externals can be a problem but do not have to be. If the external repository was on the same server then you probably specified the external with a relative URL. If the new server uses the same structure then everything should work just fine.