Ok, following up from my 5K run last week as benchmark (around 30:30) -- I did a 4-mile run today, came in about 40 minutes.
Performance timewise wasn't much of an improvement, however, I am proud that I pretty much jogged consistently throughout (as opposed to numerous walk breaks during my 5k), pausing briefly only during the 3 red lights I've encountered (which I did lateral leaps while waiting).
What I think kept me going was: 1) Doing a 5-minute warmup prior to my run, giving my legs a good stretch and 2) a fast-pace "runner's mix" of songs I put together on my mp3 player - which kept me revved up and moving.
Anyways, I look forward to making my runs a weekly thing (maybe even twice a week later on, but not getting ahead of myself now) and continue to improve my time and my cardiovascular health!