Hey, since I am the one responsible for creating all that (and our new firstboot process) I'll try to help.
The long and short of it is that the trusty repository is not kept up to date the way the precise repo is. We have a second repository that we use for development.
deb http://deb.linuxmce.org/ trusty main
Try adding that to the sources.list prior to installing your packages. The joggler has to announce itself to the router before it will be able to create devices. Be sure your networking is setup properly prior to installing packages. Once the joggler announces itself to the router the mounts (and other permissions) will be in place to boot, but not before. The core-locater is necessary to locate the core's ip, without it nothing will work.
This new firstboot process is still working through a few bugs but the above should get you working. Feel free to jump in to IRC for some real-time help as well.
Running your 1404 joggler on 1204 is not an issue, they are effectively fully compatible. I run precise, trusty, wheezy, jessie in i386, amd64 & armhf all together.