I like all of these ideas and any of them introduced would make things more interesting.
One tweak I might add to number 1 is perhaps...not linking them to an individual unit.
But more to a realm. Imagine if you will, an upcoming battle. Two realm armies are coming together to fight.
Send in the adventurers to get ground information and send it back to the army. This is the roleplaying version.
The gameplay code idea is that for each realm adventurer in a region where battle is happening, the realm warriors get a small boost in combat power. Not a gamebreaking amount of course, but enough to encourage players to do it. Either make it a set amount for each adventurer, or possibly base the shift on each adventurer's adventuring skill. That would be the more complicated way to code it, but it would make longer-lived adventurers more valuable than the young punks.
Note that if the adventurers swarmed into enemy territory before the battle (as they would have to) there is a non-zero chance that they would be arrested by patrols at turn change. Which...well...is a risk.
