I'm off to Rome in April with DH and DC aged 9 and 11. I know of all the obvious sites, but I'm a bit overwhelmed by what I need to prebook and what I don't... also whether any of the tours/guides are worth it (we do want to see everything and understand what we are seeing, but DC11 in particular has the attention span of a gnat!). We've got four full days. Thanks in advance!