Travelled with our almost two year old son. We had booked into the Apartment/Annex/Villa Mughetto and could't quite tell what we were in for. I can't comment on the the regular rooms, but at the time we booked they were double the price of the apartment. Had a large bathroom (no tub for but large walkin shower), small kitchenette with fridge and small stove and sink. Lots of space for our son to run around and on the grounds there were some grassy areas, and a nice walkway with ducks and small pebbled beach to throw rocks in the lake. Breakfast included was great, high quality, eggs per order, breads, yogurt, pastries, fruits.
The only negative would be that if you wanted to be in town, then this is not for you. It was a couple kilometer (very beautiful) walk into the nearest town Maderno, and a short taxi to Salo. There was a small store nearby (5min walk) for milk and some small supplies. We were looking for some quiet/relaxation and so it suited us perfectly.
Staff were very accommodating and friendly to our son.
FYI cab from Desenzano train station was ~50euro. Cab to/from Salo was 13-15 euro. Private driver back to Venice airport was pricey at 300euro but we needed to do it for our schedule.