Are areas outside the golden route cheaper?

Hi all!

Im currently planning a 3 months trip to jaoan, exploring kyushu and honshu, up to tokyo (maybe tohoku and okinawa, if ill have time and feel like it).

The trip will be taking around feb-may.

Im trying to realize if a 13-14k usd (excluding flights) is enough budget.

I feel like the prices listed on online guides are a bit too focused on tokyo-kyoto-osaka, understandably so, but it makes it difficult for me to determine if i have a proprr budget.

Im planning on:

- moderate accommodation, dont mind hostels

- varied food experiences-while i am a foodie and one of the reasons to travel for me is to try food varieties, but i do believe ill buy 7/11 food or even produce to cook for myself.

-5-6 hike days

-no paid attractions- nothing agaisnt them, just havent seen any that speaks to me

- im not a big shopper nor a havey spender. I belive ill spend 500-1000 dollars throughout the whole trip on gifts/souvenirs or products.

-i will rent a car for rural areas

Its important to note, this is not all of my money, just the budget, so if i go overbudget by 2-3k its unfortunate, but ill be fine