I've read that Grieg's home, Troldhaugen, is about a 20 minute walk after getting off the bus stop. Is there any parking nearer the home? A member of our group may not be able to do a 20 minute walk. Thanks.

Look at: http://www.bergenartmuseum.no/default.asp?enhet=troldhaugen&sp=2
parking is naturally close to the museum, but public busses do not go out there (for those few visitor arriving by public bus) - but you get off down at the main road, but not the closest.
Look at Google Earth - there you can measure the distance from the parking area - it is some 400-500 m = 5 min walk.
Comparing the pdf-file from the museum with Google Earth you find the walking distance from the public bus is some 1.2 km (as crows fly).