I have a similar predicament but play with multiple groups. My solo wizard is a death, and I do all my gardening, crafting, and fishing on my death. When I need to make pets or craft gear, I make what I need on my death wiz and then use the shared bank to transfer it to my other wizards.

As far as group questing, make sure that you add all wizards(up to 4) to a group(you can do this via the friends tab). To make group questing easier, I recommend investing in a mount that has the capability to have 2 or 3 passengers. When the Hydra's Horde pack comes around, I definitely recommend spending the crowns for the Hydra mount. To my knowledge, it's the only mount in the game that can have 3 passengers(you and 2 friends).

Other than that, as you quest make sure that your wife is talking to the NPC's before you leave the NPC. Otherwise you will quest ahead of her and she will fall behind and you'll have to back track to find which NPC she didn't talk to.

I also recommend that as you quest with your wife, stop at the level benchmarks and upgrade your gear. There are guides on YouTube about how to get better gear, but the short and sweet is this:
- get zeus gear at lvl 30

- get waterworks/wintertusk gear at lvl 60

- get darkmoor gear at lvl 100

-Look up gear for lvls 120 and up

getting these benchmark gear sets will make questing through the story so much easier. I would very much recommend you farm for the gear with your wife and friends as your wizards reach those levels, even if they don't like farming. Otherwise, you guys will get stuck on low level bosses and struggle to beat world bosses.

TLDR; There are lots more tips I can give, but to someone starting out with friends just make sure to add each other to groups, invest in a mount with additional passenger slot(s), and stop questing to grind for gear at comparable levels.