A DN might be a bit big to be escorting a convoy - but there is a scenario in SFB where a heavily damaged DN (I think it might have been a DNL, as opposed to a regular DN) was being towed to a starbase by a Tug, and escorted by Star Fleet ships, but the force had to contend with an interception by a Klingon force led by a C5 light dreadnought.
In ths case, maybe have the convoy escorted by a DD or two, being attacked by an enemy force, and then have the DN lead a relief force instead?
In ths case, maybe have the convoy escorted by a DD or two, being attacked by an enemy force, and then have the DN lead a relief force instead?