Vapor Recovery System leak on 2007 Prius?

Hi all,

Was on the forum forever ago when I bought my car and back now (new account) with a question for the wisdom of the group.

My 2007 Prius with 111,000 miles on it has now thrown a 'check engine' light at me twice. Most recent was yesterday. Previous was about 2 or 3 weeks ago. Took it to my local (and trusted from work for the lifetime of the car) dealership for diagnosis. The tech said they thought it could be caused by a leak in the vapor recovery system and did a "smoke test" twice but could find no visible leaks and said that could be because it was an incorrect code or because the leak was inside the fuel tank where he couldn't see. He reset the code and said "drive it and see what happens". His opinion was "if it's in the fuel tank assembly you'll have to replace that, but it's not a critical hazard because the system is all contained". Thus, my questions for the group:

1. This is a tech I've not met before and an area of my car I'm not familiar with. Is he giving me a straight answer or ignorance/misunderstanding warranting a second opinion? In short, is this an actual thing that can be an issue?
2. If true, how serious is it in terms of "stop driving now and tow the car in" vs. "eh, make an appointment for the new year to deal with it"?
3. Anything else I should be exploring?
4. Anyone else go through this and have an idea of costs I should expect?

For context, this is a "drive it until it dies and get a new car" type of car and I'm concerned I might be getting to that point where fixing it gets more expensive than just getting a new car. it's been very reliable until this year, but the rust underneath is worrying me and the list of repairs in the past three months has gotten long - wheel bearing, alignment, headlight replacement, muffler replacement, heat shield replacement, pinhole leak in timing chain casing, breaks will need replaced in the next 3-6 months, etc. Not just looking for confirmation to go buy a new car, but want to give context.

Thanks in advance.