SES vs aerobatic.... that is a whole 'nother thread in itself. I have done both and the floats was a lot more fun, and way more flight time for the money in a float course, and, the SES takes care of your BFR as well.
Where ever you go for your SES make sure that they do river work, and, learn how to ramp a plane. I got mine at a well known place (not mentioned so far) and did neither of those. I then went and ferried a 206 on floats from Minneapolis up to Homer with a friend, we landed on the Missouri twice and landing on moving water is way different (when you consider winds, sand bars and such) than lakes. Three weeks later I did the same trip in a 182 on floats this time solo. Overnighted in Sitka and had to ramp the plane. Had to call same friend (who had spotted herring there that season) and ask how to do it while taxiing at idle around the harbor in the plane. Took me three times, each time adding more and more power and thinking I was going to launch over it. Fortunately there wasn't any other float planes on the ramp at that time of year, but I am sure everyone in the harbor had a good laugh.

Mountain flying should be a course in itself, in my very humble opinion.
You should do it, and have a great time!