My SV650S K6 does a 100 mile/day round trip 5 days a week. In the last few months alone I've done just short of 9k miles.
About the value, I don't know. But basically, I'm looking at keeping mine a max of 5 years. If I do that, it'll of covered 120,000 miles plus!
So it'll be good for scrap value & not much more. I knew that when buying it though.
The spark plug issue is well covered on the forum. You can get a fender extender for £18 from a suzuki stealership, or grease it up properly. A quick search will give a full explaination.
HTH