I’ve been to a few chassanas that gave some thought to this issue and came up with what I consider a simple and clever solution. The invitations let guests decide which part of the simcha they would attend and set things up accordingly.
The choice was to participate from the beginning (the “shmorg”) through the chuppah or from the chuppah through the dinner.
That not only gave the guests an honorable way to avoid exhaustion (not to mention baby-sitting fees), but also to limit the cost of the affair to some extent.