I live near the Black Forest which has all of the above. Rivers a-plenty around here - the Rhine, of course, especially around the Lorelei. You can cruise along and see it all from the boat. The best part are the picturesque little old villages, but the nature is very beautiful in a European way (i.e., you're never far from "civilisation")
By most accounts, it can't hold a candle to the mountains and landscapes (countryside is too parochial a word) around the West coast of America, starting in the Napa Valley and working land inwards to the National parks.
I imagine Idaho and Montana to be up your street, too, whilst the States further South may be too desert-ridden for someone who loves mountains, lakes and rivers.
Bled is beautiful. At least, judging from the postcards it must be. We went there when it was still Yugoslavia and we were staying in Kärnten in Southern Austria. We did a three-countries drive (Italy, Yugoslavia, Autria) on a rainy day. We saw the lake and Tito's country house in the rain.
20 years later, my husband and I spent a holiday in Slovenia and visited Bled again. Again it was pouring with rain. The locals said "We haven't had rain like this for 20 years". We laughed and said we knew - we had been there then, too.
