Or we'll build the museums around the spacecraft, perfectly co-moving. Visitors will be able to walk around them and admire their antique workmanship as they obliviously continue their steady journey.
What an excellent tribute; I hope we have the technology to do this within our lifetimes.
"With today's technology, would it be possible to launch an unmanned mission to retrieve Voyager I?"
http://what-if.xkcd.com/38/