We had a great stay at hotel Kreuz, which is a short walk from the Leissing Train Station (several buses come to Leissing via Thun or Interlaken). The hotel was clean if a bit older but the staff was very helpful and friendly and breakfast was great.
There is a restaurant in the hotel for dinner, which was nice, but it is really the only dinner choice in Leissing. We ended up having dinner one evening in Thun and one evening in Interlaken, where there are more choices. It was a short - maybe 10 minute bus ride from Interlaken and maybe 20 minutes from Thun. We had Swiss Rail Pass so the fare wasn't an issue. Though in the evening there is only one bus an hour so you need to keep an eye on your watch to catch it else you will be an hour delayed.