Wench, I just got out my calculator. Hmm. 1/4 mile is 1320' and 6% of that is about 80'. So if that's really what it is, well, you should be able to get up that puppy in 1.5 minutes or less. So that's perfect for short intervals! Hit the hill at your normal pace and give it everything you've got. I'd stay in the saddle. Keep a high cadence and a high effort. Ignore your HR. It won't be long enough to bring the blood squirting from your eyesockets, but it will be hard. Then pedal back to the bottom, ride off for a minute or two, return and hit it again. Do that 4-8 times. That'll stimulate your systems.

The second drill is to get your HR up to LT on the flat or small rollers and hold it there for 15-20 minutes. Ride moderate for 5-10 minutes and repeat once. You'll need a lot of road room to do this - it'll be 7 miles or so. Quit when/if you feel yourself slowing. You should be right at the edge of what you can sustain for that length of time. That's your LT.

About power and cadence - that's complicated. On the flat, most folks develop their best power at a relatively high cadence - I'd say 100 is about average. OTOH, when climbing, most folks develop best power at a lower cadence - say 78 to 85. I don't know why this is so, but it is. My guess is that momentum is less on a climb, so that puts a greater emphasis on pedaling smooth circles - a complete power stroke - and that's harder to do at high cadence. Although sometimes I'll climb better at 95. It just depends on how my legs feel.

In general, if you are struggling to stay in zone, "pedal faster, you fool." That should be painted on every climb near the crest. Sometimes I'll shift down a gear and my speed and HR will pick up.

If you did each of these drills once a week, that would be good. Otherwise, just ride lots and have fun. And this might fix being dropped on climbs. Oh, and every 4th week cut out the intervals and take it easy.