There's an open ended question... and about the only answer I can give is "it depends". Some of it might depend on what your goals are, and if you want a system to take you into a future of RC for a while, in which case it would make sense to buy a more sophisticated system with more channels and options. If you're just wanting a good sport flyer system, some of the less expensive systems are still very nicely equipped as well... so on that aspect you might understand how it "depends".
As for brands, there's a few stand outs, and we all have our favorites for several reasons. I'm partial to Spektrum, with Futaba being a close second. Both offer good components, and they all work as they should as long as the end user takes time to study and learn, and sets everything up correctly. I'm partial to Spektrum because for me the telemetry options were very enticing, as well as selections of transmitters and components. They seem to stand out to me, and many other people. Service and product support play into it greatly as well, and I've not been let down by any of it with Spektrum. So with that, there's Futaba is good equipment too I used Futaba for many years with no problems...,, and now FRSky is apparently gaining ground as well, but I've not studied much on their offerings..
Most systems offered these days don't really come as a whole set, so you have to search out your own servos, whether it be for same brand or different from your tranmitter(Tx) or receiver(Rx). Most all mainstream servos are compatible with modern systems with no problem at all.
Same for receiver batteries, so study battery technology as well. There's different battery chemistry's now available as well as different capacities available, gone are the days for most of us using the old Ni-Cads. There's much better components/batteries on the market now. Nickel metal hydride)NiMh) is even going away, but some stick with those for some reason. I use LiFe's on my smaller sport planes, which is a very safe lithium phosphorous based battery, very stable, and is rated at 6.6v's, which is also compatible with most all modern systems/servos.
If you're looking at a giant scale, you can get into LiPo based, which is lithium polymer, not as safe per say as a LiFe battery, but yeilds a 7.4v rating, which for the high-voltage(HV) systems is nice, as it gives the HV rated servos extra punch and torque. I've had good experiences with all the above, and I use LiPos on my giant scale projects.
For a newer flyer, and any sport flyer though I would recommend LiFe's, and size/capacity would depend on the plane and servo-count in said plane, and what you'll actually be running off of the battery(s). You'll need a modern charger that's compatible, and most of the chargers will charge any battery on the planet, and do it in about an hour. Gone are the days of charging planes overnight. I can charge everything(giant-scale or small sport planes) in 1 hour and be ready to fly.
So from my perspective, I'd say start research transmitters, and because I'm partial I'd say look at Spektrum/Horizon Hobby and see what's there that interests you. Both Futaba and Spekrum can also be found on TowerHobbies website too... as well as the Rx's and batteries.
We all develop our favorite components over time, and when you're just starting out, it's always recommended to visit a local club, make some friends, and ask some questions. There you'll get first hand looks at what they're doing, and why. Some will also say "buy what they're using", but I won't go that far, but will say just study it for a bit.
I'm not even sure what a Royal Sr. is but it sounds like a classic model of some sort, as the name "Royal" was once the cream of the crop in kits, and I'm all for classics. If I saw one I'd probably recognize it, as I've been in this hobby for most/over 40yrs, and it's always cool when someone comes into it. Albeit it can get confusing, but just be patient, and study everything as best you can.
I'm sure I could go on.. haha... but I'm going to Google Royal Sr. and see what comes up... and I'll also leave you with the question of "what is it?"... That tidbit might help people give input as well.
I hope this all makes sense, and gives you at least something to start with... welcome to RC. Hang on for the ride!!!