What limits your bike / run?

I'm a big fan of hill repeats on the bike.  I have a number of long 6 to 10% grade climbs in my area.  I also live on a hill at 750', with the nearby lake at near sea level.  So coming up from there is a 750 foot climb in 3 miles.

One favorite is Lakemont Blvd. http://www.bicycleclimbs.com/default.aspx?ClimbId=34&RegionId=1

1.9 miles long, 651 foot gain, 6.6% grade with sections closer to 10%.

Early season is 6 repeats on that seated.  Then I start adding in standing between sections of light poles.  One season I got strong enough to do 4 repeats in a row standing the entire way up.  That's doing some work!

Best run workout;  the tempo run - 2 mi WU, 1-3 miles @ threshold pace, CD (distance is dependent on how many mpw I'm doing, shooting for 10% of weekly)

Run question:  what's the best way to improve at running while ALSO building cycling and swimming fitness? 

Best bike workout:  threshold repeats - I have a 5 mile-ish flat loop in a state park that I'll do like 3-4 times with a 1-2' recovery

Bike question:  what's the best way to maximize performance on a road bike with clip-ons?

 My best work out running or cycling always has to be done in a group.  When I am with a group a long work out seems to fly by and I feel great when it is done because I am moving in sync with other rather than trying to mechanically force myself into a set pace, set heart rate, set cadance, set power output, etc.  

Bike or run my best work out is a 90 minute training out that is done slightly fast with a lot of change of speed/effort.  The long boring details are below.

Best Run work-out:  90 minute Run. With 60 second surges mixed in.  This run was done at 7200 feet elevation on a dirt road about 10 miles out side Laramie, Wyoming.  Our track coach dropped about 15 of us off then used the odometer on the van to stop at every mile back into town.  As we passed the van our coach was there with his clip board and stop watch.  He would yell out out our individual split (i.e. 6 mins 48 sec) which was pretty impressive to keep up with 15 people because he had to know what our total time was for the previous mile and what the current running time was and then subtract out the difference for every person.  Ever time our coach honked the horn of the van we would surge until he honked on the horn again.  I did this work out 3-4 times.  We always saw herds of Antelope out running in the same area as us.  Some times they would run parallel to us which was really cool.  One of my last work outs with my team did this 90 minute runs.  I was leaving to California for two years so I knew that I wouldn't be back to run with the team the following year if at all and I knew that I possibly would never be in as good of running shape as I was at that time again in my live so my last "Antelope Run" I ran my heart out and when I was done I felt like the top of the world.  I expected to have lactate build up of soreness, but I felt like I have just done and easy 6 miler.  For me it doesn't get any better than doing a 90 minute run at a fast pace.  Running it with team mates and the antelope make it even better and having coach Sanchez read out your slips as you go by and laying on the horn ever couple of minutes for you to surge makes it more fun.

Best Bike Workout: Well this would be about the same as my best run work out.  A 90 minute ride on a country road with very few turns but lots hill.  On a hilly couse I don't worry about riding is one hear rate zone for a certain number of minutes than another heart rate zone for a certain number of minutes etc.  I know that when I get to a big hill I am going to have to dig deep and get over it.  Then I am going to enjoy a fast decent down the other size then focus on an even effort that will bring my heart rate back down and get me ready for the next hill.  The goal of the ride is ride the course as efficiently as possible.  I guess you could say It is a bike drill day to work on form. :-)  I never had had the privilege of doing this work out with a group or have a coach waiting for me at ever mile with encouragement, but for me training in a group always works out better.  I a group two hour work outs go be like nothing by on your own every minute seems to drag out.