We are paying for ours as well and have a limited budget ($5k) and FINALLY, after months of searching and disappointment, found a venue that we both love AND allows outside catering. The place was off the beaten path, and most have never heard of it, so it took me about 6 months into a one year engagement to find it and I was just as frustrated as you are. So I know exacty how you feel. When I finally found the place, I only had 6 months left to plan the wedding.
Okay, so we finally found the place of our dreams and can afford it (yay!) but after researching all of our options, we came to the same conclusion – we can’t afford to cater. So we decided to do a dessert buffet with other stuff like fruit, cheeses, cubes of bread with rosemary olive oil, etc. We are catering it ourselves (With some help from friends and fam on the baking/arranging side) and we have about 100 people to feed. The cost is SIGNIFICANTLY cheaper (for us – Atlanta is stupid expensive) and without this, we would have had to charge the catering (we didn’t want any debt for the wedding) and I wasn’t happy with any caterer I spoke with. We’re going for an Amy Atlas style for our buffets, starting the big show later (7pm ceremony) and worded it correctly in our invitations, plus posted it on our website, along with restaruant recommendations in the area. Everyone has told me they’re really excited about it, because they’ve never been to anything like it before.
I will say that it has come with it’s share of obstacles, though. No catering = no plates, etc. Yup, we’re using the nifty “real look” disposables. You have to work within your means… and that fit mine, and I’m okay with it. Since my wedding is all geometric and modern, I bought the white square and triangle plates that look retro. No catering = no one to clean up, bus tables, etc. I hired a friends mom and a friend of a friend to bus tables, replenish the buffets, light candles, whatever needs to be done.
So you CAN DIY it – especially with the help of friends and family. But it does make it harder – both logistically and mentally (stress) in some regards, and easier in others (cost). I can’t really offer advice on the venue, but I can on DIY – you could do huge bowls of salad (2-3 different kinds), bread and rolls, baked brie with fruit, a fruit display, a crudite, a dessert buffet with several cakes and pies or cupcakes, tea sandwiches, a gourmet olive display. tomato, mozzerella and basil skewers, etc. It doesn’t have to be full meal type stuff. Like you said, all things that can be refrigerated and pulled out during your ceremony. I don’t know if that was any help at all, but I wish you luck with everything!