If I had $60,000 I would move to a legal state like Cali, buy some land and seed and have at it.
But, if you want to stay in an illegal state and grow, simply buy a fixer-upper for say $35,000 down and use the rest for equipment and renovations.
Forget solar, it won't be cost effective, just put a 200 amp service in with adequate wiring to your basement grow area. You will need to get a plumber to install a sink and washer hot/cold water feed.
I run 27 plants in 3 rooms in half of my basement, perpetual, under a combination of LED/HPS totaling 7200 watts.
I been running this present system in a residential neighborhood for around 12 years, with no issues from the power company/neighbors/cops
Every 6 months the power company send me a notice though, comparing me to my neighbors, which tells me that I am using 4 times the average amount (last months bill was $432)
The 1st one I got I almost shit, now I just toss them in the garbage and pay my bill on time.
So, fuck the commercial building, buy a small house and pack the basement.
Oh, one more thing, make sure you can sell all that shit you guys plan on growing, like constantly, or your buddy is going to be fucked.