I will be arriving in Osaka on the evening of July 4 and probably staying at the Hilton (Conrad is out of my price range!). I will be attending a conference on July 6-7, but then have a few days to explore until I depart at 1810 from KIX on Tuesday, July 11. Ideally (though not necessarily) I would ideally like to stay at an SPG/Marriott property just because I can do it on points, but that looks like it leaves it pretty wide open. Not expensive non-SPG (non-western) would be OK if they weren't too expensive.

I could stay in Osaka and do day trips, but am wondering if it is worth going elsewhere for a few nights. I actually prefer smaller places with access to nature, but I have no idea when I'll be back in Japan! I've been once (5 rainy days in Tokyo more than 10 years ago) and loved it! Before I went I made it through several dozen episodes of Japanpod101 and don't think that I managed to use it even once when I arrived I admit that cost is one of the things that has kept me away.

I'd like to enjoy some great food, and might do a street food tour one night in Osaka. I'd love to see some historic castles, hike/run some amazing trails, and even just wander around beautiful neighbourhoods. In Hanoi and Bangkok in February, other than time working, I walked/ran more than 80km in a week, so even though it will be warm, I generally prefer active. The better to enjoy food and drink .

Any thoughts on different options for those few days?

Thanks!

Take the Shinkansen and do a day trip to Kyoto.
Takes around 15mins from Shin Osaka Station to get to Kyoto.

Another day trip idea is Himeji Castle. One of the best castles in Japan.
https://www.himejicastle.jp/en/

I would choose Himeji Castle and Kyoto considering the limited time available. Nara is another possibility. It is easy to run around the built up area of Kyoto or take a taxi and run around the tourist spots which are especially popular in March and April.

Kyoto is one of my favourite places in the world and recently I completed my 10th visit, some of which have been a long weekend visit from Tokyo.