To hack or not to hack - that is the question.
If you don't want to spend a few hundred dollars or more to get a modern retro style radio/cd/aux in ipod unit, then you will have to go with the original radio or hack a larger opening in the dash.
I bought my truck used 13 years ago and it came with a "pre-hacked" dash and non-working Kenwood single DIN dash unit.
I "repurposed" an old Alpine cassette/CD unit I took out of a Honda CRX I sold. I did not like the set up, so I got the cheapest Alpine head unit I could find from Crutchfield - about $100. I looks good, fits well, has a single CD slot and aux in, and a USB port. Oddly, Crutchfield says it won't take an Ipod, but will take other aux in devices - but I don't have an Ipod. I think you can get equally cheap Alpine units that will accept Ipods now. I copied about 6 albums off my computer WMA files and I keep that one CD in the unit. I have had good luck with Alpine units so I stay with that brand. My unit does have one sticky push button but it still works ok.
For speakers, the local discount auto audio shop cut two holes in the kick panels and installed Alpine speakers. It is tight in there but they do fit and look good. I got a couple of round JVC speakers from Walmart for $20 and built boxes out of 1/4" MDF for the rear cab corners.
This set up suits my needs and sounds good for few $$$.
Of course, if you need boom box mega blasters with multiple amps, disregard all of the above.
