Suggestions to make your trial more bearable... also know as "things that worked for me". Please keep in mind my pad and tape ranged from about
my shoulder blades down to my waist because of where the wires had been inserted.
Because of restrictions for bending and twisting I was grateful for the attachment to the tub nozzle, just slip it over the spout, to wash my hair. It was a cheapy I'd bought at WalMart years back for when I used to wash my dog in the tub; glad I kept it! Because the tub height was just perfect with a towel folded on the edge for padding, I was able to kneel infront of the tub, rest my chest on the towel, and lean over the tub with the long attachment. My mom put the shampoo and the conditioner in my hands as needed, but otherwise I handled the rest. Make sure your towel is close at hand!
Lots of sponge baths with a washcloth. It's not the same, but it's better then nothing. If your hair is long, pin it up and have your hubby help wash your back being careful to make no contact with the tape. Within a few days that stuff started to feel like it was peeling off; got to be VERY annoying. And from what I understand that is probably the most annoying thing after comparing notes with my friend who has a Medtronic unit, as well as my Rep.
For the first day expect to be sore. I found a pillow behind my back worked wonders. Put everything within easy reach so you don't have to stretch, and let your hubby pamper you! I was so grateful for my boyfriend spending those first four days with me.
I invested in a couple shelf bra tank-tops, and I got them a size small. It permitted me to wear something comfy without the need for a bra, and it helped keep my tape from trying to peel off. The tape /will/ shift during the course of the trial; do not be alarmed if it migrates a little. Hence the tank tops. I lived in those things! I'd wear one for a couple days then swap it out to wash it, and yes I wore them when I slept. Again, I did it to help protect the tape on my back.
The elastic band at your waist with your external unit gets annoying. You can wear it over your pants/jeans/sweats, but I found it easier to wear it just slightly above my clothes. Also, be prepared to not be able to tuck in shirts.
I'm sure your doctor has already asked you what side you sleep on perdominantly, the opposite side is where they should sit your unit. I know you don't have to take it off to sleep, but I found it more comfortable to disconnect and remove it at night. Just make sure you secure your wires either with a little medical tape or something so they don't flop around and produce a potential nocturnal hazard.
ALWAYS KEEP YOUR REMOTE WITH YOU! I don't care if you're going to the bathroom, take it! Remember your wires will probably be prone to shift, which means a sudden jump in the sensation, and sometimes that's not pleasant. In a pinch there should be a button on the unit you can press to turn it off if your remote takes to long to shut it off.
As the days go by you'll get more and more used to it, comfortable with the sensation, remote operation, everything. I know the further I got into my trial the more I was able to turn my unit up higher. If you're not getting good enough coverage call your Rep and let them know so they can see you ASAP to get the unit adjusted to give you the coverage you need. Your Rep should check in with you every day regardless. Make sure you take your antibiotics till they're all gone like a good girl; better safe then sorry.
Hmmm, I think that's it. I know you'll be scared, it's hard not to be. Those last minutes in the waiting room by myself were torturous. I sat there and cried, I was so scared. The unknown is always scary. You'll be okay though. *hug*
And remember, as annoying as the tape and wires, the sudden jolts (if you experience them, because mine were in my neck they had more room to wiggle around) the no showers and all the other little things ... just keep telling yourself "It's Just Temporary." 
Before you know it it'll be over and you'll be having the temp wires removed. If about halfway through your trial you decide this is what you want, then maybe talk to your Rep and your Doctor and let them know, see what you can do to get a jump start on the process to get your permanent.
I'm excited for you! As scary as it was to get to that point, I remember how wonderful my life was with my temp unit. I really miss it most days.
If you have any questions don't hesitate to ask! I'll answer them to the best of my ability, but please keep in mind these are based on my point of view. What works for one person doesn't always work for another... but I'm gonna think real positive, and so are you.