Jomon, Yayoi and/or Kofun sites on Shikoku?

In researching our itinerary for Shikoku, I am noticing there are several Kofun sites in Kagawa. Also, a kofun site on Awaji Island. Does anyone have any recommendation for Jomon, Yayoi or Kofun sites that are 'top of your list' on Shikoku? We have 3 weeks set aside to really explore by car, each prefecture. Also, Japan is ground zero for Museums right?...so any recommendations as to which Museum on Shikoku will educate us in the best way about this specific part of the history of Japan? Thanks so much in advance.

Many other than the Jomon period and Yayoi period are listed, but this is the ranking of cultural sites and ruins in Shikoku.
https://www.jalan.net/kankou/pro_009/g2_30/?screenId=OUW3801
https://www.tripadvisor.com/Attractions-g298228-Activities-c47-t2-Shik...
Iwaya Ruins
https://shikoku-tourism.com/spot/12327
Kamikuroiwa Iwakage Ruins
https://www.kumakogen.jp/site/education/1666.html
https://kuma-kanko.com/spot/spot737/
Kochi Prefectural Buried Cultural Property Center
https://www.kochi-maibun.jp/exhibits.html
Kagawa Prefectural Buried Cultural Property Center
https://www.pref.kagawa.lg.jp/maibun/maibun/index.html
Ehime Prefectural Buried Cultural Property Center
http://www.ehime-maibun.or.jp/
Rexyl Tokushima
https://www.pref.tokushima.lg.jp/rekishiru

Although it covers a much broader range of history as well as culture (with amazing displays and videos of festivals in the prefecture), the Ehime Prefecture Museum of History and Culture accessible from Unomachi Station in Ehime is one of the best museums I've been to in Japan.

https://www.i-rekihaku.jp/
English leaflet -- https://www.i-rekihaku.jp/guide/guide2019_english.pdf

Included in its permanent exhibition are displays on the prehistoric period and there is also a special archaeology room.

You did not indicate when you plan to travel, but the museum is holding a special exhibition entitled, "Kofun Culture of the Imabari Plain", from 7/19 - 11/26 this year.
https://www.i-rekihaku.jp/exhibition/special/2023/0719/

Nearby the museum (down the hill) there are streets with historic buildings, including a number from the Edo period and a few other museums including a school, that are also nice to visit.