I struggle with hills. I am very slow and have to stop to rest my legs and lungs. An ex smoker of 4 months after 40 years explains a lot. But I want to improve, I ride for 3 days on alternate weekends, 80km to 120 each day and include hills such as the Velloway or up into the hills via Gorge road etc. In between my weekends off I commute to the gym 3 days a week (15km each way), do spin 3 times a week on alternate weeks and have just changed my gym routine to include any resistance training that involves legs. So over 14 days I exercise one way or another on at least 10 or 11.
I'd be interested to hear any suggestions on how to further improve my hill climbing or perhaps change what I'm doing.