Search the apple website for "retail stores".
2) How dangerous is using mail order to save some money on the MACs?
We've had no problems, though we haven't used the one you mentioned. You can order from apple, too.
3) Does the MAC come with a paint program? How does it compare with some of the freeware/shareware or even commercial PC programs? Are there any freeware/shareware "paint" programs for MACs? Any decent (but simple) commercial paint programs? She may eventually also get Photoshop Elements for the MAC, but I have no doubt that this would be WAY beyond her. As I said, she doesn't really know anything about computers, and she has a HUGE phobia about them.
Macs come with iLife which is iPhoto, imovie, iBlog, Comic Life (which, if she scrapbooks at all, she'll love), photobooth, etc. I highly recommend Photoshop Elements. It's not any more complicated than any freebie "paint" program.
4) How is file compatability between PCs and MACs? I figure that I'll either burn all of her work to CDs or maybe copy them onto a flash drive to move to the MAC. Are MACs OK with bitmap (.BMP) files? I'm sure that they're probably OK with TIFFs, PCX, GIF, and JPG (or am I assuming too much?)
It's the 21st century.
5) She would like to be able to use some of her existing hardware if possible..
Shouldn't be a problem. Macs and Wacoms go waaaaaaaaay back.
She might like this program for her cards and graphics... I have it, and am more than happy.
There is a free demo, so she can try before she buys. I use it for everything from designing needlework patterns to preliminary design drawings for my Architect husband...