We stayed for a week in the middle of August with our 10 month old daughter (not crawling). Mario was very accommodating and provided a travel cot for her to sleep in.
Using our own clip on high chair, together with using the washing machine and dishwasher our stay was very comfortable.
Everything in the flat is clearly labelled and there is a great suggestion book provided with all the detail you need
The flat is very near to Market street - one of the main streets in SF- and is also close to Union Square.
We found Mario to be very organised and helpful with suggestions of what was happening in the city while we were there.
We would definitely recommend this flat for a couple with or without a small child.
Thanks for letting us stay in your place Mario.