Day trip from Tokyo to Matsumoto

My wife and I are visiting Japan for the first time next month (Tokyo: April 13-17; Kyoto: April 17-21). We know we'll be too late for blossom in Tokyo/Kyoto, but I noticed Matsumoto gets its blossom a bit later.

* Would it be possible to do a day trip from Tokyo to Matsumoto on April 15th?
* Do you think the cherry blossom and castle in Matsumoto is worth prioritizing? Or choose a day trip somewhere else? (e.g., Nikko, Hakone)
* According to https://www.japan-guide.com/e/e6053.html, there is a direct train from Shinjuku Station which takes 2.5 hours. Is it reasonable to do this round trip in a day and have enough time to explore Matsumoto castle?

Thanks in advance for any advice you can give!

I've not seen the cherry blossoms at Matsumoto though we have been there a few times, including about 10 days ago. The castle is definitely worth a look, it is one of my favorites although personally I prefer the little one at Hikone near Kyoto. I think you could get there, see the castle and wander around and then be done within 3 hours.

I wonder whether you could leave Tokyo early morning, train to Matsumoto, poke around, then get on the Chuo line to Nagoya through the Kiso Valley (quite a pretty trip, probably late blooming sakura there as well) before arriving at Nagoya and changing to the bullet train for kyoto? Doable, but a long travel day.

If you wanted to be really adventurous, you could stay overnight at Kiso Fukushima. You get great bang for the buck with their ryokans there, the area is getting more popular with people walking parts of the Nakasendo Way. I hope I didnt confuse you...

A day trip from Tokyo to Matsumoto is do-able.
If it is a day-trip, you can leave the itinerary open (possibly with few options) until the day (since you don't need to reserve a room).
Then decide where to go depending on the blooming status that day.