Shikoku has many beautiful sights and sounds and the trip from Ehime to Takamatsu gives you the opportunity to take in most of those.
Both Ehime and Takamatsu are in the north of Shikoku island and one route highway will give you the trip between both areas.
Ehime includes the wonderful Dogo Onsen on the outskirts, and from there you might consider taking a trip to Dogo Onsen. Shimanami Kaido offers a beautiful alternative between the route between Ehime and Takamatsu.
Takamatsu has several nice areas nearby, including the famous Naoshima, Kotohira and Tashima Island.