When we have split stays, we usually have WDW move our stuff.
Since you only have a 5 day stay, I am going to assume you won't have huge amounts of luggage.
We pack up in the AM, call Bell Services, have them transfer the bags,then go to whatever park we're going to. When we're done with the park, we go to the new hotel and check in. Usually our bags are there & they get them to the room relatively quickly. That's been OUR experience. We do tend to have a bag with our bathing suits in ti that we keep with us so that just in case we get to the new hotel and our bags aren't there we can still use the pool.
The poster who suggeste done bag for one hotel and one bag for the other hotel...that's not a bad idea either. You can wear all the clothes out of the one bag and then stuff them all back into the bag when you leave the 1st hotel and then not have to look at or open that bag again till you get home.
I tend to unpack my suitcase when I check into a hotel room and then put the dirty clothes back into it as I take them off. Then when I leave, the suitcase is ll packed and all I have to throw in are the toiletries.