400s and winded

In an attempt to reach my goal of running consistent sub 8 minute miles in time for Ragnar Vegas I was looking around for a few speed workouts. The biggest challenge I'm finding is that October is almost too far away to start using Speed work to train for that, however I know I want to be faster for my halfs too, so I need to find a balance.

I found an article in this month's edition of Runner's World that talked about improving your time using 400 repeats. 

Basically take your average mileage pace, divide by 4, then subtract 10 seconds from there to get your ideal 400 time. Since I don't have an average mile pace because I'm all over the place, I decided to say it was 8 minutes (probably not smart) 8:00 / 4 = 2:00 min, subtract 10 and you get 1:50. Well I negotiated with myself that the article was referencing 5k times, and my average mile for that would be high 7s, soooooooo it wouldn't be too big of an issue if instead of subtracting 10 seconds I subtracted 20 seconds. 

1:40- didn't seem too hard, infact I was thinking it was rather slow considering I used to run 400s back in the day... oh silly Lisa when will you learn. 

I didn't have a lot of time on my hands, so driving to the track and back was out of question. I decided to get some good function out of my Garmin and run around my neighborhood to see if I could find a 400 straight away (or close to it as possible bc sometimes the Garmin is iffy) 

I was in luck that the last house on my road and up to the stop sign was 400 m- behold... my make shift track... complete with a slight uphill going one way. If you click on picture to enlarge, you can see in the distance where there is a cross road... that is my ending point. 

The RW plan said to do 5x400 at your pace (1:40) and then walk 400. Again crunched for time I decided to just rest for 1 minute. 

I finally got to tinker with my garmin and used the interval setting- since I already had my 400 meters laid out, I just put it in for a countdown of 1:40 and then a 1 minute rest for 5 repetitions. 

First one was miserable- I didn't realize I was running uphill or that there was wind and I myself was 'winded' much before hitting the stop sign- wow I suck at pacing. 

I wish I could say the next 4 were easier, but that would be a lie, I was still tired each time I reached my end point--- maybe next time doing them on the track wouldn't be such a bad idea because then at least I know the entire time what distance I'm at.

Does anyone out there do non track speed workouts? 

OR anyone do 400 repeats? 

I've read a lot on 800 repeats as well, I'm just in my experiment phase to see what works best for me... todays workout, not so great.