I've had a few inquiries over the past few years from newbies wanting to see a "day in the life"
Although I was not, and am not, looking for a trainee, I was glad to set up a day for them to see (partially) what goes into an assignment
I had them go with me on an inspection (each time it was a vacant property - I would not bring them to an occupied property)
I explained what I was doing regarding measuring, walking through the property - what I'm looking at and notating - photos, looking at the surroundings/neighborhood
Obviously this inspection took WAY longer than my normal one does, but I made the time and factored that in
I did have one person who met me at my office. With that person I did go over the preparation I do before an inspection and then went over the post inspection; showed them MLS, etc
So even if an appraiser is not willing to take on a trainee at this time, they may be willing to have you sit/visit with them
It may not hurt to offer to "buy them lunch" or "pay them for their time" ... Personally I did not/will not take compensation for the above mentioned, but that's just my personal business model. But offering that may help you get the attention of other appraisers in your area
FWIW, I am strictly RES. Good luck