Mercury Fleetfoot:
Horses don't really do stealth, so the forward positions are likely better for riders who can notice threats. If we need to fight I will be abandoning the pony to save itself.
Sure you're more stealthy... in woods
In the Rohan plains, stealth is not an option, and Berthold (and probably Herubrand) are the ones better knowing it and more used to Cavalry scouting.
And, as you said, if combat occurs, you'll have to abandon your pony, and you'll probably need it latter, so Berthold keeps suggesting you to stay with the main group, where ponies may be kept even if fighting on foot.
Admina:
Is there a cart or wagon in the group ? I thought I read that somewhere.
Yes, Worth has one (post #18
The gates of Minas Tirith):
Wort Halffield:
The pony and cart would be seen to, he knew, but for a moment, it felt like he was on the edge of a great chasm.