hi, if you go online and find the Swiss travel service, you can buy your vignette. Remember of course you need one per vehicle, and there are weight restrictions, a different price if your motorhome is over a certain weight.
If you don't buy your vignette before you go, worry not, all the border crossings have offices to buy one. The border guards wont let you cross without one, therefore can get very busy at certain times of year.
Once we were settled at our campsite, we were given free bus passes and found the bus service stopped right outside the camp, and ran quite regularly. The prices of the train passes could only be described as jaw dropping, the deal we bought gave us 6 return journeys , a return journey each on the boat around Lake Thun and half price on one other, the exchange rate at the time wasn't that great, and the deal cost close to £300 , but by far the easiest and quickest way to get up to the beautiful villages, however we didn't use our car the whole time we were there, lots of deals and offers, it just depends on how much you are prepared to pay and where you want to go. We came back poorer, but wouldn't have missed it for the world. Enjoy the scenery it is to die for.