Basically what your looking for is going to be winstrol and anavar.
Both are dry compounds, both give decent strength, and both should increase both running speed and muscle endurance without much weight gain or water gain.
Your cardio/respiratory system will still be a limiting factor, and generally when I was a runner back in the day my lungs gave out before my legs.
This leads to lactic acid in the legs, and you slow down, etc, etc.
which brings me to the second fold, albuterol.
Now, heres what I suggest.
Winstrol and anavar are both avaliable as orals, both are pretty mild health wise, and both are pretty mild in terms of natural test shut down.
You will need a PCT eventually which means an SERM, these are available quasi legally through research chemical sites.
For you I would say winstrol and albuterol, var is harder to get than winny, winny is extremely common and fairly cheap.
Albuterol is cheap and easily obtained either through an online pharmacy or the better option is to go through, agian, a research chemical site to obtain the liquid form.
Albuterol seems to have a fairly significant increase in athletic performance, and has a relatively short half life, combined with benadryll you should be able to use it for a majority of your cycle.
I myself have used albuterol before as I actually have a perscription, its very clean, you get the shakes when you first dose it but those go away.
people have been using albuterol for athletics since I was in highschool, we used to pass around inhalers and take like 12 puffs for an adequate dose. And on that note most Olympians are "registered asthmatics" so they can legally use albuterol.
You will need taurine and pottassium supplementation while using the albuterol as it does deplete taurine stores and cause some cramping.
The strength, endurance, and speed from the winny combined with the increased speed, somewhat strength, and cardio/respiratory efficiency from the albuterol should give you a pretty fun ride athletics wise.
Before we go any further I think its a good idea for me to mention that winstrol is an AAS and you will need to obtain it illegally.
If you can get the winny your cycle is simple from here on in.