Staying on Hilo side with young kids- how long?

hi, we're planning 3 wks on the Big Island, and through recommendations here on BPN are thinking of staying in the Kapaho area- with the naturally warm lagoons. We're starting with 10 days in a condo in Kohala, where we're really excited by being near the beach, near a couple pools, hot tubs, and not too far from everything.  We want to explore the Hilo side as well, but with a 1 yr and 5 yo, we're really looking for a kid-friendly situation. I'd like to plop the kids down and not worry too much about them- beach seems easier than rocky lagoons.  And we're thinking of 2 days in Volcano to check out Volcano NP.   Don't want to have to move around too, too much.  We've been told Kapaho for more than 3-4 days is a bit long. But in posts here on BPN people seemed to love it. So- how long is too long in Kapaho?  And, any other ideas for staying on the Hilo side?

Any thoughts or ideas?  Thanks!