First, how do experienced players and GMs balance the difference between Mechwarriors and non-mechwarriors? If there is only one Mechwarrior in a group, what can the rest of the group do during that conflict?
Like many others have stated, also AToW Companion, balancing Mechwarriors and non-mechwarriors is a challenge.
For first timer games, I don't really recommend it too much, but it could be done.
Mechwarriors in some circles are nobility.
So even if the Mechwarrior is not in the cockpit of a Mech, he or she could wield power in the halls of a palace.
Then again you've wasted the one thing that a Mechwarrior is famous for, the giant avatar of death they ride.
However if the stars align and everyone really just wants it, there's ways to play it out.
Solaris VII, one of the famous star systems for gladiator fighting, is a great place for various types of people and adventures to play in.
One mission happens to be the Mechwarrior in his ride, the next is a technician and a shady dealer making rounds to find rare parts to keep his ride going.
If he doesn't win matches, no one gets paid.
However he needs them, he doesn't know a wrench from a plasma torch.
Or maybe getting the Mech
is the goal.
(Link provided) One of the Free RPG day scenarios happens to be a group of people tasked with stealing a Mech.
That would be a good way to start a campaign for a team, or make a fun one shot adventure.
Second, and somewhat connected, in Battletech, are there mechs with multi-day crews? If so, could I give gunnery to other members of the party so they could shoot while the pilot pilots the mech?
Mechs and pilots are typically 1:1. One pilot, one ride, and much like the knights with their armor suits of old, difficult to part with.
There are rules in TacOps for Dual cockpit Mechs, but I would see using those mainly in a teaching fashion than actual fights.
Third, how would you suggest creating a game for people with absolutely zero Battletech experience? Are there certain eras and scenarios that would be ideal for this group ignorance?
In terms of story structure, pull anything from a book and add lasers or giant robots in.
One novel, Sword and Dagger, is
Man in the Iron Mask with Mechs.
That's not hyperbole and overall it was a simple nice story leading people into the Battletech Universe.
Now as for eras, personally I think 3025-3039 works well for the scrapper mentality.
2750 and parts earlier work nice for a "this is the shiny future" type of mentality, probably the closest we ever got to a Star Trek style. ;)
Regardless of era though I recommend a small scrappy unit who are put together due to circumstances.
If you're going the House route: A collection of misfits ordered to fight pirates and take on jobs the Regulars snub their noses at.
If you're feeling Mercish: The remains of a betrayed mercenary command are putting things together. They'll take any contract which keeps their bellies full, armor on the rides, and ammo in the bins.
If you're feeling a bit pirate: Actually either of the two variations above could work. Maybe these were people falling on hard times.
Scrambling around for work, legit or otherwise, and if they have to "liberate" things so be it.
Or possibly a shadow group formed by their government. They target friends, enemies, anyone the "higher ups" deem worthy.
If they fail, they'll be disavowed. It is a small price to pay in order to do what really need to get done for your House.
Really just take on how people are introduced into a movie or book's universe.
There's usually the outsider looking in, the reader/viewers proxy.
Simple missions at first, clear objectives.
Provide some story showing the aftermath, an after action report as it were.
All the while drip in some Universe information, so the players don't feel like they're studying for a finals.
Have a Drac trooper in your group get their butt
kicked hard in a nearby Davion tavern.
Why did that happen? Well you are in the Draconis March and you were still in your old uniform.
The players will then get the feel for certain environments after that.
Also don't be afraid to simply throw stuff out the window and make your experiences your own.
Canonicity only goes as far as the table wants, even then some throw that out the airlock and have fun with it.