<human>: Give me a shortened version of the text

The situation: My FW and I have chosen to get married at the camp we met at and worked throughout college, but that venue can only hold about 200 adults comfortably. The reception venue can hold about 400 comfortably, which is where our total guest list is at (My FW has 4 parents, 3 of which come from very large families). Our tentative plan is to only invite our immediate families, closest friends, people who have traveled to attend, and people who worked with us at camp (many close friends) to the ceremony; and invite everyone else to just the reception. My FW is worried about offending people by only inviting them to the reception. Especially since it's not a particularly small wedding venue, but our numbers are complicating things. 
So here are my questions:
1) How big a deal is it that people have only been invited to the reception?
2) How do we word and send invitations to make it clear but polite?
<bot>: Guest list ~ 400, Wedding venue capacity: 200; Reception venue capacity: 400. How do we invite people to just the reception without offending?