The Bern valley is nice. On the SE side are spectacular alps, on the NW side the Jura which go up to a few thousand feet, and offer interesting walking if that appeals.
Grenchen (LSZG) is a super little GA airport on the Jura side which we used a visit to Solothurn last June. Bern itself may be a bit pricier.
If you have experience of bigger airports, Zürich (LSZH) is doable and relatively inexpensive, though now has compulsory handling so it's a bit more hassle than it used to be. PM me if you want more info.