I'm guessing you already found a solution, but if not, I ended up drilling a hole in the firewall next to the steering column when I installed my gauges. There is also a plug behind the accelerator pedal where the throttle cable would run on a gas truck that would maybe work. How do you like the avh-p4200dvd? That is what I am thinking of getting to replace my stock stereo, so if you have pics of the install I would love to see them!
I ended up routing the antenna wire through the dash and out the left side of the dash into the rubber door insulation, up the door and out on the roof on the driver's side. There's about a quarter inch of the wire visible where it leaves the dash and enters the insulation. I'm very happy with that - much easier than drilling a hole in the FW and probably exposes less wire.
The AVH-P4200DVD is fairly awesome. A few comments about installing and the product:
When removing the factory radio, get a speaker removal tool (coat hanger didn't work for me) and make sure you don't shove it in too deep - just about a half inch to an inch deep until it lightly clicks, then gently pull outwards and pry it out.
I ground the top and bottom of the factory hole with a drimmel. There's a lip that's about a quarter inch high on both top and bottom, just grind it all the way down. Be careful with that dremmel though - don't accidentally touch the outside dash or you'll leave a nasty mark.
I used this Metra bracket to fill in the spaces on the left and right because a double din radio is slightly narrower than our factory radios. It fits perfectly with this bracket and looks awesome: Metra 95-5817 (met-955817) - Dash Kits - Sonic Electronix
I cut the old factory wiring harness plug off and manually wired the new Pioneer harness on using Chilton's manual for the color codes. It's in the back of the book. However Chilton's didn't tell me which speaker wire was plus and minus and I didn't want to accidentally wire them out of phase. So I found this list on a spammy website. Reposing in full here:
1999 Ford F350 Car Audio Wiring Diagram
Car Radio Battery Constant 12v+ Wire: Light Green/Violet
Car Radio Accessory Switched 12v+ Wire: Pink
Car Radio Ground Wire: Black/Light Green
Car Radio Illumination Wire: Light Blue/Red
Car Stereo Dimmer Wire: N/A
Car Stereo Antenna Trigger Wire: N/A
Car Stereo Amp Trigger Wire: Blue
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: N/A
Car Audio Front Speakers Location: N/A
Left Front Speaker Positive Wire (+): Orange/Light Green
Left Front Speaker Negative Wire (-): Light Blue/White
Right Front Speaker Positive Wire (+): White/Light Green
Right Front Speaker Negative Wire (-): Dark Green/Orange
Car Audio Rear Speakers Size: N/A
Car Audio Rear Speakers Location: N/A
Left Rear Speaker Positive Wire (+): Gray/Light Blue
Left Rear Speaker Negative Wire (-): Tan/Yellow
Right Rear Speaker Positive Wire (+): Orange/Red
Right Rear Speaker Negative Wire (-): Brown/Pink
A few comments about the AVH-P4200DVD:
I have the Pioneer CD-SB10 and the Sirius SCC1 (about $100 together from amazon) to listen to sirius. I'm not super impressed with the integration. The Regular sirius units let you scroll through lists of stations to pick which one you want to switch to. This unit isn't as user friendly when integrated with the AVH. You can only see the station when you change to it and the display is slow to update so skipping through stations is slow. But the audio quality is MUCH better than my old sirius unit that rebroadcast on FM into my radio.
The DVD player is awesome. I did the (illegal) bypass of the parking brake switch so my wife can watch DVD's in the front dash on road trips. I'm considering getting something to block my view of that part of the dash for safety. DVD quality is great, no skipping, audio is awesome. Here's the bypass video I used:
My favorite feature is the SD card. I ripped 8 gigs of music onto a $20 walmart SD card and just got back from driving to and from Colorado Springs (from Denver) and my wife and I enjoyed great tunes the whole way. You can literally take your entire music and possibly movie collection with you.
The FM radio is great.
The AUX input is great - I've run a $20 quarter inch dash mounted jack to the quarter inch aux input in the back of the unit. I plug my Android cellphone in and can use apps like Pandora, tuneWiki etc to stream music (at surprisingly high quality) from the cell network.
One complaint I have is that I can't mute the speakers and have a headphone output that is not muted. I want someone to be able to listen on headphones without distracting the driver. I'm considering getting 4 of those Bosch relays and running a mute switch to the dash. There's got to be an easier way to do it though but I don't know enough about electronics to know if there's a kind of relay that will open/close four separate circuits. If anyone knows of a piece of hardware that does this, please let me know!!
The sound is surprisingly good with factory speakers.
Next step is to upgrade all four factory speakers to 6x8's (or possibly use component speakers - separate tweeters and mids). Then get an amp and a sub installed under the back seat (crew cab). I may also power the four speakers from the amp, but that will mean a pricier amp and complex wiring, so still debating that. The unit has 4x50W so not bad in terms of power.
Hope this helps someone.