couple suggestions: That's about a 1500W element so you'll be drawing almost 15A from your wall plug with it...hope you have some headroom there. Keep extension cords as short as possible and make sure they're made up out of at least 12AWG ("12 guage") wire. Also, note what your PID controller can switch. If not well over 20A, I'd give it a break and get one of these $4 relays to do the heavy switching:
http://www.ebay.com/itm/24-380V-40A...363540?hash=item2ee7515854:g:mi0AAOSw~bFWH3gH
If you have 240V handy, stovetop filaments work great, will give you twice the power, and are cheaper than the Brinkmann. But I assume your controller is 120V?.
Now the specific heat of water or meat is 1 cal/g/K = 4J/g/K and that of steel is .5 J/g/K. Now if you have 50# = 22kg of just thawed meat loaded up you'll need to change its temp by ~80K (or 150degF) so you'll need 4*22*80 =7000 kJ = 2kW-hour of heat. Your Brinkmann 1.5kW running constant with no other losses will do the trick in just over an hour. Since I assume you'll want longer smoking times than that for culinary reasons, your Brinkmann should be able to get the job done as long as you don't have a lot or losses, like too much air passing from intake through exhaust.
Now you may have 100# of interior steel in that Crosley that you need to heat from room temp to a 220deg smoking temperature. That's also a temp change of 150F or 80K so your 100# = 45kg of steel needs .5*45*80 = 2000kJ = .5kW-hour of heat. Your Brinkmann (without other losses) can get that part of the job done in under a half hour. But why not just get it all heated up before you put in the meat? Close off your intake "damper" so you're not wasting energy or time passing hot air through the unit. (Just make sure the exhaust is open, especially with that locking door otherwise you're heating a sealed container, the recipe for a bomb.) Then load in your meat and amaze'in smoke generator and let the controller take over. Slowly open up the intake damper until you get nice smoke flow up the exhaust stack. I wouldn't exceed a 1" exhaust for fear you'll lose too much heat and you don't have enough brinkmann power to keep things hot. (But I suppose you could use a bigger exhaust and install a damper/flapper on the exhaust as well so you have flexibility.)
My opinion on fans is that they might help smoke flow faster over your meat and give you more smoke flavor. But that's only if they're mounted INSIDE the smoker and both intake and exhaust of the fan is the hot smoky interior...so they work like the fan in a convection oven. If you're just blowing in cold air from the outside with an aquarium pump you might as well just open your normal intake that much more so you pass that cold air over the amaze-in apparatus and MAKE smoke with it.
What I suggest instead, since you have lots of room and are using rectangular shelves, is to take some thin sheet stock, the depth of the interior but cut a couple inches narrower than the inside width, and hang them an inch or two off each rack in your fridge in an alternating left-right fashion so you form a smoke labyrinth inside your smoker. The smoke will spend more time in the smoker and it will be moving faster as it passes over each rack of meat. And this is an easy experiment to try both ways, with and without. I'm kind of surprised a guy like Greg Blonder hasn't tried it already.