I know @ClassyJalopy doesn't need to break his in, but here's ECGS's guide on breaking in fresh R&Ps (although you should check with your builder--since it was freshly set up with new [hopefully tighter than factory] tolerances, you may want to do some weak-sauce version of the below--maybe reach out to the builder?).
New gear sets <b>MUST</b> be broken in correctly to prevent damage. Not following proper break-in procedures will lead to overloading and overheating the ring and pinion as well as breaking down and ruining the gear oil. Not following proper break-in procedures can be determined during...
eastcoastgearsupply.com
As for time required, two days is probably _plenty_ (if you have the right pullers should your ball joints refuse to release, and an impact wrench to get them to get back together when they want to spin away from your ratchet). Could probably be done in a day barring any super-stubborn ball joints or anything. If you've pulled the hub knuckles and changed CV axles before, you're looking at that plus probably 45 min to undo and drop the diff, and probably an hour to get the new diff up there and bolted up (that's how long it took me anyway, IIRC--harder to get the diff moving against gravity than with it . . . and that was with a gracious wife operating the floor jack). Then assembly is the reverse of disassembly.
Don't bother fighting cone washers and undoing hub flanges--some folks say to do that, but the FSM doesn't, and it's not necessary.
I tried the "leave the lower BJ still connected and wrestle the axle back and out" method but couldn't get the axle out of the knuckle for the life of me.
For wiring, if you're in a hurry to hit the road and don't need the locker, you could just zip tie the harness under the hood and hang down the business end (I zip tied mine to my raised breather line) and connect it to the diff and leave everything else disconnected. Depending on your under-hood setup and how you choose to get switched power, all the wiring can be done in probably 1-3 hours. Getting one more wire through the firewall was the only thing that took me a minute. . . but it's pretty straightforward, esp if you mount the relay under the hood somewhere and already have an accessory fuse box.
Feel free to PM me with any questions--having _just_ done this I might provide something helpful. . .
But, yeah, unless this a journey you have no hope of completing without a front locker, I'd wait til you're back. . .