If you are physically moving a DP from one location to another to speed rapid deployment during your company's rolling upgrade, simply creating offline media would be faster/less prone to error. Buy a couple USB sticks, use the MMC to make them bootable
and contain all the packages, then go to town.
There are some things stand-alone media cannot do like Auto Apply Drivers and Software Updates. Also, if you are using task sequence variables to define software to install during the TS that won't work either. Basically, anything dynamic doesn't work so
it really depends on the TS whether stand-alone media is a good fit or not.
Many folks have used the concept of a mobile/traveling DP to deploy system. It's as simple as adding the system to the correct boundary group and making sure DNS is up to date. That's it. As mentioned by the others, no need to mess with fast/slow, the clients
will find the content on the DP and ignore any existing DPs in the same boundary group because presumably they don't have the content required by the TS.
It does beg the question though if you have a local DP, why not use it? You can use pre-staged content on a mobile USB drive to transfer the content around the same way you would a mobile DP. I guess it depends upon the all of the details which are not necessarily