There are two museums to see along the way:
A well-reviewed museum that closes at 6pm, several parks, and a beach.
Stedingu Maja - Resto & Kohtumispaik for dinner or
Kohvik Mantelahi or
Pubi nr. 17 (lots of reviews)
Kohvik Pannukas for breakfast the next morning
Haapsalu → Viljandi Museum → AHHAA Science Museum Tartu → Võru
Haapsalu → Tartu → Võru (4h30m 354km)