Avios redemption is pretty decent value, esp. if you go from ITM to HND as both have cheaper city-airport transit options than KIX & HND (also much closer to the cities).
You might want to check out the English highway bus reservation sites
https://www.japan-guide.com/e/e2366.html
The Yukata Liner Bus shows up here for me:
https://www.kosokubus.com/en/search/area/00027-00013/