Mounted Knights (Armoured Cav) as PCs and adventuring.

[Arduin]

As I was reading over the Knight & Paladin classes in the PHB it got me reviewing past campaign (going back 3 decades) and how having one or two PC's in the group as mounted armour never worked out that well.

Unless you are running a "Knight" campaign the role is too restricted. It doesn't work when dungeon delving. City adventures don't fit. About the only place in general adventure where it has advantages is when doing overland wilderness travel. Once at the destination, kinda useless. There is also the problem of safeguarding the precious war-horse when they must be left behind to adventure "inside". Pack animals are easily replaced.

Just thinking about how to really incorporate these PC types into the average group...

[zombiehands]

Well if you are doing a typical dungeon crawl there is no good way to incorporate horses, same thing for a naval campaign. When you have some overland travel they really shine. Knights are a bit more crippled, but paladins have enough abilities not to be truly hindered. I am adopting a house rule in my game that lets a knight use his inspire, CHR mod times a day, and have it confer a flat +2, and allow paladins to use their healing hands CHR mod a day healing Level x2 each. But these modifications are more about our style of play which does not like a lot of camping. While I think the Knight modification makes them a lot more fun to play, the paladin one is really not needed.

[Arduin]

When you have some overland travel they really shine. Knights are a bit more crippled, but paladins have enough abilities not to be truly hindered.

Right of course. My point being that unless you are continually doing that and NOT terminating your travel at places where the expensive mount becomes useless and or endangered, the mounted combat stuff is a fairly useless class feature.