Some quick thoughts:
1) recognize that if painted in the 40's or 50's this paint most likely contains lead - so be careful if doing any sanding. Use a facemask, toss rags, etc.
2) Howard's-Restora-Finish is a good cleaner for the inside. Lemon oil & 'Feed & Wax' are more hype than function. Wood doesn't have to be "fed" - in fact the reason a finish is applied is to prevent moisture and oil from getting to the wood. As to Lemon oil, think about how much 'oil' you can get out of one lemon. Now think about how many lemons it would take to make one bottle of lemon oil. If you do the math, a bottle would cost almost $100.
3) For the outside, you can also just wipe down with rag dipped in paint thinner, followed by a rag dipped in a solution of water and a few drops of dishwashing soap
4) It's going to be difficult to get a good match with new paint next to 60 year old paint . It may be easier (and would look better) if a fresh coat of paint was applied to entire surface.
Bob "Boardman" Borders