I took my 72 year old Mum to the States last October for a month... she is on a number of medications daily.. and was understandably concerned about travelling/baggage etc..

She ended up carrying a letter from her GP outlining what drugs she had been prescribed.. and she carried enough for the whole trip in her carryon.. and an equal amount in her checked bag..

No problem anywhere......

I think your plan is a good one...^