My next steps were to move ROMs across so that I'd actually have something to play, then scrape the Internet for some metadata about them, including box art, developers, release dates and descriptions. Games stick in our memories, of course they do, but trying to remember the exact title in the world of 'Super' this and 'Super' that... I wanted to at least help my future self by scraping that data.
After that, I'd try to connect up some different controller options, including a PS3 controller, and hope to get a second player up and running.
Copying ROMs from one place to another is a piece of cake, so long as your Raspberry Pi is on your network. I used Cyberduck, logged into the Raspberry Pi from my MacBook, found the required folders and moved things into place.
Because we're talking old school games, the further back in time you go the smaller the file sizes (generally speaking), so for the most part, even with a small 8gb memory card, you won't be pushing the envelope for available space, and so you won't need to be picky about which ROMs to transfer.
It's wise to be picky though - why waste space on games you won't play? Transfer the games you know you're going to go back to again and again. Just make sure you check the file type with the RetroPie wiki. Some emulators can handle a wide range of file types, others need a specific one.
Depending on what you're emulating, you might need to look into BIOS files too. At this moment in time, I've not hit such an obstacle.
Once on the Raspberry Pi, you can use a scraper in RetroPie to gather up all that info to make a list of games into a more helpful list of games. You can choose from a couple of websites to get data from, which systems to search, and some degree of how automated the process is. I chose to check everything. Let's just say it took a while. Some games are found easily, some not at all, some are named slightly differently...
All I'm saying is be prepared. I did so much scraping, there were moments where the Raspberry Pi just stopped for a minute before allowing me to carry on. I don't know whether I was pushing it too hard or what, but the process took quite some time before I was happy with it.
Of course, I had a fair few ROMs to go through. Fewer games, less time spent scraping.
Once that was done, I dabbled with controllers, which is where I encountered a few more problems. I had a USB SNES controller that worked, mostly, but not fully. Some of the buttons weren't registering in game. The solution was simply to remove the configuration files for controllers and start again, and the solution worked (thanks to the RetroPie forums for that one...)
By this point in time, I had a working USB SNES controller and even a working PS3 controller. It had to be used wired because I didn't have any Bluetooth dongle for the Raspberry Pi, but it worked.
And then it didn't. Then things went bad.
During the whole resetting of configuration files and adding controllers from scratch, I somehow ended up accidentally installing the Xbox driver required for Xbox controllers. At the time I thought "oh well, I'll let this install and ignore it - I don't intend on using an Xbox controller".
From that moment on, my PS3 controller would only be recognised by RetroPie as an Xbox controller. Which it wasn't. And so the buttons - when they worked and were recognised - were all wrong.
I'm still stuck with this problem. I've not tried my second PS3 controller, but I'm too paranoid to do so in case the controllers are forever recognised incorrectly. I might need an update, I am on a beta version, I might even need to bite the bullet and buy an Xbox controller (but seriously though, why are the analog sticks in the wrong place?!).
As I mentioned previously, I knew to expect problems. Reviewing the situation, I've actually got a large number of positives compared to the few negatives.
I've now got a hefty library of old games to play once more. Not everything, but certainly enough.
I've got a controller that works, and actually covers more systems than I thought. I've not yet tried playing a six button Mega Drive game with a four face, two shoulder button SNES controller, but if RetroPie says it's possible out of the box, then damnit it's possible.
It's not the best built controller. I'd like to have the quality of a proper controller instead, like a PS3 controller, but at present that's completely out of the picture. Player 2 still hasn't been set up, but seeing as I've two identical USB SNES controllers, I can't see that being a major problem (read 'part 4, a major problem to set up' here...).
All in all, the RetroPie is finally in a state where at least one player can be happy with it. Not bad for a few days work, a few learning experiences and not a lot of cash at all.