You don't need to stay at the Disneyland Hotel to stay 'on property'. There are 6 Disney hotels within a ten minute walk of the park gates. Then there are a bunch of other 'non-Disney' hotels that have sprung up around the park in recent years. (Holiday Inn Express etc). The Disneyland is the flagship hotel, but in my view unless money is no object you should think about staying at one of the other Disney hotels. The experience is more about the parks than the hotels. For a mid-range Disney hotel look at the Sequoia Lodge. We have stayed there a few times as well as the Santa Fe (budget Disney - but very acceptable) and the Disneyland. Of course I don't know your means or your budget so that one is your call. In my experience the Sequoia Lodge would work out at least $1000 less for five nights - probably nearer $1500. In reality, you wouldn't need 5 nights. 3 or 4 would be enough - see below.
Ask away on this thread if you want to know anything specific about Disneyland Paris, or even Paris itself. From getting from the airport to where to buy the best hot dogs!!
By the way, 3 days is more than adequate to go to both parks when it is quiet. You would spend no more than one day in the Disney Studios and two in the main park. You would see everything in that time, including shows and parades. You might also want to think about Buffalo Bill's Wild West show in the evening as that's worth a look.