Brick workout - Biking AFTER running

Some of my workouts are reverse bricks, so I don't think you would have much harm doing it in that order.

However, I try to do most of my brick workouts in order, to get the race day feel in my legs.

That's what duathletes do, so it shouldn't be a problem. Switching things up to fit into a schedule is better than skipping something. I like to ride my bike to the pool (the short way), and then take a longer route home.

It's all good!

is there nowhere else you can run? say down some sidewalks or anything?

I swim/run and bike/swim sometimes just to give my legs a break from the bike/run. I dont think it matters much, it still a training session. Just make sure that you do get in a few bike/run bricks in before a event.

i do these a lot, and it will vastly improve your triathlon cyling. you never start a tri bike leg fresh, (or a duathlon) you either have a swim or run before, so its good practice, and it also serves another key pourpose. if you are limited in the time you can spend on the bike, cutting out the warmup is the most time effective (yet not recomended if you can help it), so the run first allows you to warm up on the run and go straight to the main workout on the bike.

i do these almost as much as bike/run

I've done them too.  I found them surprisingly hard.  Not used to starting biking with tired legs in training, so it was helpful. 

I did run/bike all winter long. I like to run outside, but when it gets dark at 5:00-5:30 I could not be out there for that long. So, I would come home, get my run in (3-9 miles depending), then come home and jump on the trainer for 1-2 hours. Doing that has definitely improved my bike this season.

Now that it is light until 9:30 pm, I mix the bricks up all over the place.

E.g. Swim/Run, Swim/Bike, Bike/Run, etc...

Sure, why not?  My bricks workout is typically riding my bike to the track, running, then taking a nice easy ride home.