These are pretty good Optionetics articles. Essentially, a long-term call can be thought of as owning an underlying stock, especially if it’s an in-the-money call and an expiration date farther into the future, because it has intrinsic value and is a more long-term holding than a front month call that you would sell against it. I did something like this on AAPL in November: bought a 2-month 75 ITM call, sold an 85 strike front-month calls for 2 months.  It worked out nicely as long as AAPL stayed above my long-term call’s strike price (75) which it did. And since it’s ITM I get more delta on the 75 strike’s gains.  My goal is to just get the calls I sell to pay for my theta (time decay) costs of owning the longer term call, which makes it cheaper to own than owning the stock outright.

Part 1
http://www.optionetics.com/market/articles/20794

Part 2
http://www.optionetics.com/market/articles/20826

You could also consider something like this using synthetic stock but it brings more downside risk.