Transferring from one resort to another is easy...check out of the first resort and give your luggage to Bell Services...they will transfer your luggage to your new resort (during an "intra-resort time frame"--when we last did it that time frame was from between 1 and 3 in the afternoon)...when you get to your new resort, call their Bell Services and they'll bring your luggage to you (you have to be in your room to receive it -- that's different from Magical Express--you don't have to be in your room for ME to deliver your luggage). There's no charge for the luggage transfer (except for tips to both Bell Services CMs)...
As for getting yourselves from the first resort to the second, you can take a Disney bus to a park or to DTD or to any "hub" that will allow you to catch transportation to your new resort, or you can walk (e.g, it's an easy and very pleasant walk or boat ride from OKW to SSR (or visa versa)...there's also a boat from POR to DTD and then on to SSR and/or OKW)...to go from one resort to the Epcot area w/out going thru DTD, you should take a bus to the STudios (used to be MGM, now it's Hollywood Studios)...it's actually no different than going from your resort to a different resort for a dining reservation...
YOu can also take a cab...last time I took one, it was from SSR to the All Stars (where I met some family for b'fast and it was before the buses started running)...it was $15...
So long as you don't expect the whole transfer to be accomplished in just a few minutes, you'll probably find it easy and painless...