North Japan

Dear All,
We might have extra days (4 nights) before heading to Tokyo and start our trip south.
Where do you recommend to go in the North? I am looking for an area where to stay for the whole 4 days and do daily trips of the surroundings from there.
Any suggestions? Hokkaido? Tohoku?

I recommend a place that is of personal interest to yourself:
https://www.japan-guide.com/list/e1101.html
https://www.japan-guide.com/list/e1102.html

If you are interested in cities, then you may be able to do the entire trip by public transportation and stay in one of the cities of northern Japan.

If you are interested in natural attractions, then renting a car will make things considerably easier and broaden your choice of possible bases.

What time of the year are we speaking?
And what are your general interests? Nature? Culture? Cities? Hiking????
Is renting a car an option?

Tohoku and Hokkaido are both enormous, so getting a bit more of an idea what are your interests might help. Plus there is obviously already a lot of information on JG for you to go through to get some initial idea.

That was one of the first questions I had as well - when are you traveling?
Renting a car can enormously broaden your travel possibilities. A lot of places are not conveniently reached by train or bus, if at all.
That said, driving through isolated, icy mountain roads in the winter with lots of snow if you're not ready for it may not be the best idea either...

It doesn't even have to be what most people think of as "Winter." There are roads and places that do not open until Golden Week and can still see snow then. Back in '09 within 3 days I visited Kakunodate for peak sakura and Hirosaki just past peak, but got caught in a blizzard at Towadako in between.

But I think it really does vary by interest and time of year.

North of Tokyo, 4 days, one hotel..., hmmm...
I would spend 2 days in Nikko and 2 in Aizu Wakamatsu area.
You can stay in Utsunomiya, near Nikko, where Shinkansen stops for ease of access.

Utsunomiya is nice but nothing really special in itself unless you really like gyouza :) It does make a good base for exploring though. I went to Nikko & Mito from there, if my trip coincided with the plum blossom season at Kairaku-en I'd do that again. At other times I'd probably stay in Sendai & visit Yamadera & the Sanriku coast.

We are going in July.
We could rent a car if it’s more convenient when travelling in the north …

Hokkaido… go to Biei and Furano for the flower fields, especially the lavender. It will be a little cooler in Hokkaido, as compared to the rest of Japan.

There is also a silly belly button festival at the end of July, if that fits your time frame.

Good Luck, in planning your vacation.

Recommending going to Tohoku.
You can base in Aomori and do day trips to Oirase Gorge, Lake Towada, Mt. Hakkoda, Mt. Osore, and maybe Hirosaki.
Lake Towada: https://visitjapan-vegetarian.com/lake-towada-aomori-japan-a-stunning-...
Oirase Gorge: https://visitjapan-vegetarian.com/oirase-gorge-discover-the-most-pictu...
Mt. Hakkoda: https://visitjapan-vegetarian.com/hakkoda-ropeway-yakeyama-the-prelude...
Mt. Osore: https://visitjapan-vegetarian.com/mt-osore-aomori-japan/

For Oirase Gorge/Lake Towada and Hakkoda, I'd stay at Yakiyama or Lake Towada for a night, to be honest. You should be able to leave your luggage in the hotel in Aomori. They're usually happy to do so if you're heading back for another night (one hotel I checked with even agree for me to store my staff even though I wasn't going to spend another night there).

You can buy Tohoku highway bus Ticket
2 Day pass= 6000 yen
3 Day pass =8000 yen

There are lots of places in Tohoku. As far as bases go:

Morioka is convenient for accessing Hiraizumi, Ichinoseki, Hanamaki, Ryusendo Cave, etc. in Iwate as well as Kakunodate, Lake Tazawa, and Nyuto Onsen in Akita.

If wanting to explore Yamagata Prefecture, Shinjo is well-placed for access to just about anywhere in the prefecture, with train lines that go west to Sakata where you can transfer to reach Tsuruoka, Yuza, or Mount Chokai or going south to Yamagata City with Yamadera and Mt. Zao, Ginzan Onsen, Tendo, etc. You can also access Naruko Gorge and Naruko Onsen easily. Hijiori Onsen and nearby scenic rice paddies are also accessible from Shinjo, as is the famous "Totoro tree".

Aizu-Wakamatsu is a good area for 4 days in Fukushima Prefecture, giving you access to the Aizu region and Mount Bandai.

Hirosaki or Aomori City are good bases in Aomori. In July you may be able to see the famous rice paddy art in Inakadate, visit Mt. Osore, explore Hirosaki City's castle and castle town, visit Lake Towada and the Oirase Falls, visit the Shirakami Sanchi World Heritage Site, etc.

If you want to visit Matsushima, Sendai is the best base. Sendai, to me, doesn't have the best nearby options, but you can access Yamadera from Sendai. Shiroishi Castle is nice. Togata Onsen, Akiu Onsen, and Sakunami Onsen are there, as well.