ellaryk

I have a 40 year old Raleigh racer with 27" wheels that I'm trying to use and make comfortable. I'm 72 and very fit but have a bad back.
I am replacing the racing seat with a wider seat so I can avoid groin discomfort.
I have raised the handlebars so I don't have to lean over so much but with the racing handlebars I'm still leaning forward about 20 degrees from vertical. On a long ride this puts a lot of strain on my arms.
Can I replace the handlebars with standard handlebars? Is the only limitation the length of the brake cables? Any recommendations on this?
A more radical change would be to upgrade the derailleur system. Mine has levers that are attached to the handlebar post. No numbers. Shifting is done by feel. This isn't a comfort issue but a convenience issue. Am I right in assuming an upgrade would require replacing the derailleurs and cables?
Thanks.