There is a Gozo ticket that covers a few museums (some are not memorable but price is reasonable) at 13 euros (go to Hertage Malta website) They also have the multi site pass that covers all the Neolithic sites, all of the Gozo above and many other interesting sites for 30 days (50 euros); we found this one very good if you are planning to visit many places. Last but not least, if you are only planning to see these temples, there is a joint ticket with the windmill for 5 euros.

Yes, very accessible for a wheelchair

I did not take any tour. Had a bus pass & went on my own.. very easy to do & just up the street is the windmill. When I did take an island tour I did the hop on hop off bus, well worth it to get your idea of distances & where everything is.

its not that big both is only 2 min apart and the temple is small and the windmill is small space u can explore in 30min

Sorry, i don't know because shen we went there was closed.

Yes - all the buses on Gozo go from the rim to the centre and vv, so its easy to get to Ggantija, tho you often have to wait up to an hour. It's well worth it.

si, e non è economica

Yes, there is a fee. You pay the fee when you enter the museum part of the exhibit. The fee is 9.00 per Adult.