I'm sure this is a problem many people have ran into. I've seen things about it in many places, but I haven't really found a good answer.

I've been running Hoard of the Dragon Queen and rise of Tiamat for my group for a long time. We are coming close to the end of the campaign and we are at a point with a massive battle between several faction from our side, as well as the opposing side. There are several different armies on both sides, assumingly numbering in the thousands, as well as other groups like metallic dragons and even giants all fighting against their evil counterparts. The campaign book does a bad job with relaying what we are supposed to do with that. Basically some of our assets can "cancel out" those on the other side, but it feels bad to just gloss over the massive battle just to get the PCs past it and into a dungeon where the final battle may or may not take place.

Has anyone had success in playing out this specific encounter, or even one similar to it? I have read the UA mass combat rules, but some who have played it say they will never do it again. Just trying to find a way to make this gigantic battle between armies a memorable end to a 3 year long campaign.