Hi,
I have a digital Canon 10D SLR (which has ISO speed comparable to 100-1600 film speed) and a film SLR- both with at least 300mm zoom capabilities, plus a Kodak DX 4900 and a Nikon Coolpix 5000-- AND I have used all of them at Disney. When thinking about whether to take digital, film, or both, a lot of your decision might rest on what kind of pictures you like to take and what capabilities your cameras have.
First, you can get great prints made for your digital pictures-- and some online services do both matte and glossy prints (I have tried several, right now I like photoaccess.com (?) )-- so don't worry about the printing-- everyone has given you great ideas, especially Costco and Target. And the Epson Stylus Photo printers have great archival, long lasting ink.
Second, although I have used both my Kodak and Nikon digitals at Disney, I personally have found them frustrating-- neither had enough zoom for me or a quick enough response time-- but for many people they work great-- I loved them for scenery shots and shots that could be staged, but when my son turned around to spontaneously run back and hug the characters or did something in quick succession, I often missed the "defining" moment because of the camera "scan" lag. So I used to depend on my film SLR for those moments. So think about what kind of pictures and moments you want to capture and the ability of each of your cameras-- quickness of response/ shutter delay, film speed, flash capability, optical zoom-- that will most likely make the decision as to whether to go digital or film or both.
However, as an aside, I take a lot of pictures when we are at Disney (think in excess of $500 for developing for each trip-- even using cost effective developing places)-- and not all are definitely "keepers." (What's the old saying about 2 per 24 pictures turn out to be keepers even for professionals?) So I was finding film to be very cost inefficient and frustrating, not to mention a pain with airport security (I usually have them handcheck all film because I know people whose pictures have been ruined by the xray machines who had 400 speed film). Therefore, on our last trip two weeks ago, I basically just used the Canon 10D digital SLR-- I could check my pictures immediately, reshoot what I missed, and only print the keepers (0f course, I did not delete the others.) I will never go back to film for taking tons of pictures of my vacation-- the Canon took phenomenal pictures-- and would snap five or six in a row without hesitation. Diane