天理教日光大教会 by Eugene Fanyfied, on Flickr

神橋 by Eugene Fanyfied, on Flickr

二荒山神社 by Eugene Fanyfied, on Flickr

二荒山神社 by Eugene Fanyfied, on Flickr

日光真光教会 by Eugene Fanyfied, on Flickr

大猷院廟 by Eugene Fanyfied, on Flickr

逍遥園 by Eugene Fanyfied,

Hmm you may want to allocate more time for Toyosu if you plan to have lunch there. Upon moving, the restaurants are less and area is smaller - causing extremely long queue in all restaurants. Especially when you're planning to head there on a Saturday too... my cousins saw all the queues and gave up immediately.
But honestly speaking, since implementation of the minpaku law governing AirBnB in Japan, it's no longer as cheap as it used to be. The price these days are comparable to Hotels. Sometimes when there's deal/ offer or voucher, choosing a Hotel could actually give you more value - as one of the forumer pointed out in earlier posting.

Hahahahaha even though it comes with a kitchen, i rarely find anyone actually uses the cooking facilities other than hot water and microwave. My cousins were full of tenacity and ideas about cooking before heading to Tokyo. When we were there, they gave up on the idea as they were too tired. For simple/ cheap breakfast, getting sandwiches from Family Mart or a tortilla wrap (which you can heat up in microwave) or making instant noodles (only using hot water) is usually sufficient unless you have spare time to make food in the morning or evening. Imo holiday is where one escapes from cooking or chores! Then again, this boils down to preference and time.

As for washing clothes - this round i chose to pay ￥300-￥400 for a laundromat rather vs the washing machine in airbnb. The reason is simple: lack of space. The airbnb is very small and with a big group, we are already lacking the space to hang our coats and towels... thus even if i washed them at 'home', there's nowhere to hang my laundry to dry. In winter, it's also harder for your clothes to dry especially thicker clothing like jackets and jeans. End of the day, i went to a nearby laundromat, within walking distance from accommodation. In the evening after dinner, I threw my clothes in for wash and head home first. After 45min, went back to laundromat to move them into the dryer. Since the house is packed with little space to move around for 9 people, I actually preferred to lounge around the laundromat where there's chairs and vending machine. Then again, this is just my personal preference.

Btw some hotels also offer laundry facilities or can divert you to the nearest laundromat. This is usually not an issue because not all locals have a washing machine at home, and even if they do, it may not have the capacity to wash bulky items like blankets etc. Thus if you ask, the Hotel will be able to divert you to a nearby laundromat.

I've only stayed in 4-Star Hotel in Japan once during a work trip. Other than that, all my personal trips - the Hotels are 3 stars or below. Like you mentioned - it doesn't affect the travelling by large... except in AirBnB it's slower due to a big group - as there's a need for 9 people to share 1 toilet, as opposed to Hotel, with 3 people to 1 toilet.