I think having the ceremony and reception at the venue is so good. We are doing the same. We have 1.5hours between the ceremony and reception. Given that you don't have to drive to a photo location and then to the reception 1.5-2hours is heaps of time! And it is definitely not rude, photos between ceremony and reception is a typical and expected thing! Anyone who complains about it is the rude one.
We have organised an extra hour on the bar and also canapés for guests. Our location encourages guests to walk around and explore as it is a heritage listed farm so that will keep them entertained. I am also making a mixed track of music to play in the background while everyone mingles.
I am also having a table for people to write in a guest book, do a fingerprint tree and an "advice for the bride and groom" book. The below link is the fingerprint picture incase you haven't seen one.
I think the time will fly by for the guests. By time they do the rounds of saying Hi to other guests (which they won't really have time to do before the ceremony) and nibble they won't be bored.