Walking along today's Old Tokaido is to find out what modern society has done to Japan. Actually there are few places in Old Tokaido I can truly recommend to tourists. So historical houses remain only at out-of-place parts of Old Tokaido such as Okabe, Futagawa, Fujikawa, Akasaka and Goyu. Some landmarks has been restored just before quadricentennial in 2001.
When going to Sattatoge Pass trail many choose first to go westward to Seikenji temple then turn back and go eastward. Given the duration from Okitsu station to Yui town about three hours take aside at least two extra hours if you also want to visit Seikenji temple, Minagushiya, and Zagyoso. So plan the trip so that you can take at least five or six hours in both Yui and Okitsu areas.