There is a bus that picks up from Explorers, Magic Circus, Dream Castle and Kyriad. It's the same bus so can get quite busy. We've stayed at all except Explorers - we loved Dream Castle and Magic Circus as they had the better rooms and lovely breakfast. Did Kyriad for one night and was fine, but wasn't impressed with the room itself. Fine for just sleeping in though - and we didn't have breakfast. The bus does a strange route around those hotels - we found that Dream Castle was one of the last to be picked up and was therefore really busy and hard to get a seat, whereas Magic Circus was much better and you could get a seat more easily. Also with drop offs, Dram Castle was left to last (frustrating after a long day!)/ Can't remember for Kyriad!
The buses are fairly regular. Just they can be crowded, and the hotels aren't really close enough to walk to as an alternative option.
I would stay in MC or DC again, we liked both. Kyriad for the odd night - if we didn't have children, it would be a cheap option for a longer stay, but with kiddies, I wouldn't want to spend longer there. Long story. lol
However - do you already have tickets? Or annual passes? If not, packages with the
Disneyland hotels themselves may work out cheaper. Especially if you weigh out a few options such as... (assuming you want two rooms, 2 ladies sharing in each) booking 2 rooms (plus tickets as part of the package) for 1 adult only in each, the other two ladies purchase annual passes and get added to each respective room for the cost of local taxes (a few euros) on arrival. If you don't mind all sharing together, you could get an even better deal on 1 adult purchasing the room, and 3 with annual passes.... worth a play on the dlp site! Then the annual passes give you money of shopping and restaurant bills too....
C x