...I am looking at an opportunity that would have me be a protégé for an RIA who is planning to retire in 5 years and wants to train me to takeover his books which as of now he has 40 million under management. He has been in the game for 30 years and left a Big Bank after 20 years due to the MBS crap that was going on.
..."and wants to train me to takeover his books which as of now he has 40 million under management."
That's all I had to read to come to the conclusion that you are sitting on a GOLDMINE, and quite frankly, it would make a very wise decision to take the offer, provided of course you are certain about going the RIA route.
Remember, the most difficult part is to get others to trust YOU with THEIR money! From what you've stated, there's an opportunity to manage an already established client base and you'll have five full years to transition into the business.
At 1%, you're looking at $400k annually, minus overhead and compliance costs. If he's splitting any fees, perhaps that annual override is lower, however it's likely that your net income is still far greater than the $100k at your prior Fortune 500 job, and without a corporate boss to deal with!
Regarding your own trading, like the OP said, it's tricky. Some attorneys will warn you not to trade personal accounts while managing money for others. There are LOTS of disclosures to follow, and you will face more scrutiny with compliance audits. A relative of mine chose the independent RIA route, and he was advised against having any personal trading accounts. I also know of an individual that worked at a large bank for around 20 years, then took a select group of clients with $1 million or more, and only serviced those accounts. He had Schwab as the custodian, which also provided compliance and operational support for his investment advisory business.
Also, ask the manager what license(s) he currently holds (or find it with the link below). You may only require the Series 65, or perhaps you'll have to get the Series 66, Series 7 and an insurance license (Series 6).
You can ask him about compliance costs. If he's running a "one man show" then you can outsource a lot of it. Here's a link that provides some guidance as to costs. It's not overwhelming as one may think. Many RIA's are "one man show" operators, and are running their own shops with FAR LESS than $40 million. Since you're moving into a turnkey business, you won't have many of the upfront and marketing costs vs. any new RIA.
http://www.ria-compliance-consultants.com/annual_compliance_program_investment_advisor.html
As mentioned, you can look up his CRD# and find his current licenses with this link.
http://financial-advisors.credio.com/
Best of luck!