How to record a mashup?

Sorry if this has been posted before.....I'm on holibobs at the moment in deepest darkest Devon on one bar of 3g signal (it's taken nearly an hour to post this question with the network keep cutting out.....)

I have a bride next Friday who requires a very specific mashup/remix (call it what you will) of Billy Ocean songs....no problem so far.
I'm more than capable of doing this on the night....but....it get's complicated....

Mr is a prison officer (I didn't find this out until I spoke to the guy that's going to be shadowing me on the night) and there's going to be a LOT of off duty prison officers at the wedding. So, an idea pops into my head to make it a little more fun to insert some "Norman Stanley Fletcher" type clips into the mix.

So....because of the complexity (and it's also bloody dark in the venue), I'd ideally like to do the mix "offline" and replay it as one track on the night just for safety's sake if that makes any sense.

Is there a way anyone knows of that I can pre-compile what I'm trying to do as one MP3 and just play it out on the night?

The go-to answer would be to use Audacity. It's great for doing audio editing work and it's quite easy to use yet really quite powerful. And, of course, it's free!

But I used to use a program that was included in a Nero suite of software I bought once. It was called Nero SoundTrax. It was a multi-track audio editor and you could load in all the clips you wanted to use on their own tracks and mix, blend, cut and paste til your hearts content. I was once asked for a wedding song that was a choppy-mix of Heaven (Candlelight Mix) and Apache (Jump On It). The problem is I was asked for this on the night before the wedding! I didn't want to risk mixing on the fly for a wedding first dance so I was up til the early hours pre-mixing it. The result was really quite good.

If you can find Nero SoundTrax I can't recommend it enough. If not, then Audacity is a great option, too.

I wouldn't record a mashup. I'd just do it in place in an editor. I tend to use Sony Vegas for any audio work. It's easily the best editor for the money. Yes I know it's a video editing program but any NLE (non linear editor) is going to offer multiple audio tracks, effects & decent time compression/pitch shifting .
You can usually pick it up (the non pro version) on Amazon for around £25.

Audacity is okay but I don't find it as quick or easy to use as Vegas. Oh and Vegas is very good at video too by the way.

Adobe Audition.

Are you trying to make a medley or a mashup or a remix?

A Medley is easy to make and the suggested software above would probably be alright.
A Mashup may require much more advanced features especially if the vocal isn't sung to a computer generated beat and in perfect timing. A good program such as Cubase or a simple program like Mashup by Mixed in Key would be my advice
A Remix of decent quality would need a piece of software similar to Cubase, Logic, Ableton Live, FL Studio and a fair bit of time to get around their steep learning curve and massive manuals!

It sounds like you're not interested in getting into this regularly so I would probably advise Mashup by Mixed in Key. I've not used it personally but I think the other programs are good they make.
My concern with Audacity would be that you'll take hours learning how to use it properly then realise you need something it doesn't have then go and get a "proper Digital Audio Workstation" and learn it all again. I've not used it but I've tried others and wasted a lot of time before buying cubase... It's only about £50 or less on ebay for an old version.

Thanks all

Sorry for the delay in coming back....been travelling up the M5 all day then straight out on a gig this evening....the fun never ends.

It's probably more of a medley to be honest, with some of the Porridge cuts over the top of it....nothing too complicated.
I'll have a look at the suggestions above tomorrow morning when I'm awake and I've got a spare couple of minutes.

I hope for good. I'm also going o start this profession.