Only Yamagata or combine with Sendai?

We have been to Japan many times and visited almost every prefecture. We like to make stopovers in Japan when traveling from Southeast Asia (where we stay sometimes) to North America (where we stay sometimes). I will soon be passing through Japan for 2 or 3 nights (although I can make it 4 if I really need to).

I have opportunity to get a cheap flight to KIX and then from ITM to Yamagata (arriving at 2pm). Yeah, the airport transfer is a bit of a hassle, but it is cheap and convenient flight times.

On the departure we will be taking the Shinkansen to Narita and flying out at 6pm that day (so no stop in Tokyo)... it's no problem to check out of hotel and reach airport with that schedule.

I love Sendai (had a night there last trip and want to return), but have never been to Yamagata. I have been to Yonezawa one a long time ago. Is ti advisable to spit up the time between Yamagata and Sendai? It seems very easy to travel between them.

I guess it would be a night in Yamagata, then stop in Yamadera (is this worthwhile as it is still hot in mid September?), and continue on to Sendai for 2 nights where we will comfortably enjoy the city.

If Yamagata is nice, I suppose I could stay there 2 nights for a 4 night total trip (even though I originally expected our usual 2 night stopover).

Staying all in Sendai and doing day trips would be fine, but the good flight would be to Yamagata. A lot of people seem to think it is boring and nothing to do there, but we always end up having fun doing nothing in nearly every place in Japan that we have been. Sometimes we need the time just to sample regional cuisine.

There is not a whole heap to do in Yamagata city, but it is a good base for Yamadera Temple and Yonezawa has some things to do and supposably very good beef.

Well, first you don't say anything about your interests. I have been to Yamagata City and Yamadera. The city is not the most exciting place but there is something to see just about anywhere. The question is if your time isn't better allocated somewhere else, like Matsushima if you haven't seen it yet.
For what the area offers, you also might look at:
https://yamagatakanko.com/en/

I haven't been there is Sept or Oct but I'd love to go see the Kawanishi Dahlia Garden near Yonezawa.

BTW there is no shinkansen to Narita. If you want the fastest way there, you take the shinkansen to Ueno in Tokyo, then the Keisei Skyliner to Narita Airport. There are slower and cheaper alternatives as well though.

Yes I meant Shinkansen to Tokyo and the NEX (if I had a rail pass), but in this case without rail pass, Ueno to Skyliner makes sense (depending on if seats can be reserved, and how easy or difficult to transfer is with luggage due to steps, etc.)

We may send the luggage from KIX to NRT and carry a tiny bag. The comfort is well worth the cost, I think. They are just two roller bags�c no big deal�c. Small forUSA, but cunbersome in Japanese mindset.

Our number one interest is food.

We like to walk around. Yamadera sounds nice, but I�fm not all that motivated to do 1200 steps in hot weather. I�fd rather do it
In winter, fall, spring. And I can surely get back to the area. That said, i may end up doing it if motivated.

I am almost certainly spending 2 nights in Sendai. Could be 3. That�fs how this started.

But I didn�ft love the idea of flying into Sendai airport. I thought of flying into Yamagata, spending a night, and then an hour train to Sendai.

I�fm trying to determine if this is an opportunity, or a headache.

And if one night will be enough in Yamagata. Arrive 2pm and leave any time
Next day. If it really deserves two nights, i can make it happen.

This trip is happening in the next couple
Days. Last minute booking

You could go also to Zao onsen from Yamagata. If that is of your interest.

And regarding Yamadera, it may depend on the day of it is still hot. Today I am in Nozawa onsen and it�fs actually quite cool. But you can�ft be sure about the weather now tgat you�fll have when in Yamadera. But I wouldn�ft exclude it completely. And Yamadera is quite easy to get to.

The train ride between Yamagata and Sendai is quite scenic. Since you say you are able to have fun doing nothing almost anywhere in Japan (I understand what you mean, as I am the same way), I would not hesitate to spend a night in Yamagata. Nothing dumb about it. You can surely find a good izakaya or restaurant, and a few things to occupy yourselves for a while. I have never spent time there except in the station area (to change trains), but it�fs a decent-sized city, not a small town in the middle of nowhere. Then leave for Sendai the next day and enjoy the scenic ride. I wouldn�ft hesitate to do this myself, to take advantage of a good flight situation.

If it�fs too hot for Yamadera you probably aren�ft going to want to be doing onsen bathing, but there is an onsen (Sakunami) along that train line to Sendai that looks sort of nice. I once looked into going there for day use bathing (Ichinobu had a nice day plan, if I recall correctly), although I ended up not doing that. It might be good on a rainy day. There is also a Nikka whiskey distillery sort of near Sakunami station if you happen to have a keen interest in Japanese whiskey. (They apparently run a shuttle bus from the station on weekends, otherwise access could possibly be a little challenging.)

Sorry, I forgot that your actual question was whether to stay in Yamagata the whole time or not. Personally, I would probably tend to spend only one night there, but you should be able to find enough to do to keep you busy for even four nights there, including possibly a day trip to Sendai on that scenic train line�c It�fs not very far.

Yamagata has a tourist information center, and what I would probably do if I planned to spend more than a partial day in Yamagata would be to stop there after I got to Yamagata Station. They will likely have all sorts of ideas for things you can do. They will also have paper maps, which for tourism purposes can often be much more useful than Google Maps.