It really depends what you want to do and how to spend those 30 hours. Will you have a car? Or will you use a public transport, that really limits distance, as children might not be comfortable to take a trip to Balloch or Edinbugh. Will someone else be with you and help with child? etc. I would not go to Edinburgh with wean and in July - tourist places there might be too packed with people - literally, like sardines. I've visited Edinburgh couple of times but it was to get to Fringe and drink. I recommend visiting Edinburgh, when it has festivals, but not with 1 year old child, which might limit enjoying all that Edinburgh is offering.
I am not native Glaswegian, so my perspective might differ - I'm originally coming from tourist city(that I will not mention here) and when I was living there, I was not bothered by sightseeings, as I walked past them(and in a hurry) every day. So, from that perspective local people might see things differently from visitors.
I'm still exploring Glasgow and some years ago I've found that it has many green parks and I decided to visit them all(so far I have covered all the parks of southern side), so from this perspective I can recommend visiting:
Balloch is nice... but I would probably find couple of more places(in the addition to above mentioned) I would recommend over it. Also, it has some unspectacular walking required(through huge parking lot) to get there and to find those attractions. Traveling with boat on a lake doesn't sound much fun to me - too much open spaces for wind and this is the place where I had encounters with too many midges(!), so I would rather recommend visiting Riverside Museum, Tall Ship and take a Ferry across the river to Sunny Govan and gaze on Victorian Gazebo there, than remember Scotland by horrors of those bloodthirsty monsters.
So, yeah, if someone else is helping to look after kid, I would recommend visiting SnowFactor in Braehead, if summer is too hot and you are into anything with snow or wall climbing.
However, if the trip is in mind, as a sightseeing trip, I would rather recommend to go with car to Fort William(over Edinburgh) and stay in hotel there. Getting there and making all the stops and pictures might be 8-10 hours long journey - with all the stops on the way. I've done quite exhaustive ~18-20 hour round trip - visited a lots of places(including Balloch) that I had on my list... almost crashed into row of caravans, because the person next to me distracted me with sightseeing and I looked just once... Yeah, I would recommend to do a trip to that direction, but not as a driver :D Roads are not straight there.
If trip is in mind, but not long and just to look out of the window on scenery, I would rather recommend going to Greenock just down the Clyde river and back.
Or take a trip to Lochwinnoch with Castle Semple Loch(or you can take a train to get there). IMO, much better place to visit than Balloch - you can walk there and see some birds - in nature and RSPB Lochwinnoch has info and is full with kids. And if there are any midges, then they are not as aggressive as the ones near Balloch. To be fair - I have been to Balloch more times than to other places - the main attraction is Loch Lomond and the most memorable time for me was in March, when mountains opposite coast had snow. Rest of the times it was not as impressive to visit and I was more impressed by visiting other places - also trip there takes some time.