Another option is Schlabach’s. They have a fairly good selection of sweet cherries on Krymsk. They have White Gold available most years. My trees from them came on Krymsk 6. Trees run about $20 ea.
They are Amish so you will need to write a short letter asking for a catalog and send them a check for $2.00.
Schlabach’s Nursery
2784 Murdock RD
Medina, NY 14103
Another vendor is Grandpa’s orchard. They carry White Gold most years.
As far as difficulty Sweet cherries have a bunch of issues. Carefully selecting the cultivar (White Gold is a good choice) helps but brown rot, canker, insects, birds, etc. can be very difficult to deal with. Tart cherries are much easier. I would look at these threads to get an idea of what your up against and they also has a fair number of tips that will increase your chances of success.