Yes, I used epsom salts this year and think they made a positive difference. The tomato fruit does not need sunlight to ripen. The fruit gets its nutrients from the leaves of the plant. It sounds like you didn't trim the plant too much, which is good. In the future, you should just pluck out the "suckers" which are new branches growing out of the fork between the stalk and where the leaf attaches.
There is a separate tomato forum here which is a better place to get responses for those questions in the future.