Your red Cashin Tote Shopper is absolutely gorgeous - hang on to that wonderful Boyfriend!
Below is the link to a thread that I did about rehabbing a 1960s Cashin bag. It was in bad shape and I gave it the full spa treatment - including dunking her in the bath - and she came out great! But it was a tan bag and red is a difficult color to rehab. I've had mixed successes and failures with several red bags,
@Lake Effect is the expert on rehabbing red bags and she will be better able to advise you. Congratulations!
https://forum.purseblog.com/threads...y-can-still-be-beautiful-rehab-reveal.742282/
The link below shows before and after pics of 3 red, vintage bags that I rehabbed and they all got a bath and came out well, but none of these bags were as old as your bag (they were from the 1980s) and none of them were lined. I'd probably try surface cleaning your bag first - maybe use baby wipes on the lining? Frankly, your bag looks pretty good just the way it is right now.
A word of caution, I have noticed that some red bags get a bit splotchy looking after conditioning, and the splotches may last for awhile, but eventually they get absorbed into the leather and disappear. At least that has been my experience.
https://forum.purseblog.com/threads/red-hot-in-nyc-three-bag-rehab-reveal.755638/