https://www.youtube.com/watch?v=liAvzCShQLQ
You can load high quality .30-30 with your Lee Loader just fine.
I did and many others did, and many still do.
The above link takes you to a You-Tube video about simple low-cost loading .30-30 and casting bullets for it.
The video shows an electric lead melter but you can use a cast iron lead pot, casting ladle, and a Coleman stove or hot plate instead.
The author of the video uses an inexpensive press, but the information is still useful.
If you follow the instructions in the Lee Loader box, use the dipper, charge info card, and one of the powders listed (IMR-3031 is great) it's very easy.
That is for factory jacketed bullets however. Cast Bullets will require more equipment obviously.
If you stick to the powders listed and use the dipper, then you don't need a loading manual.
The Lee Loader only neck sizes brass, however, and leaves the body of the case as is. That means that brass fired in one rifle will probably only fit that rifle after loading, and may be sticky in another rifle's chamber. Chambers vary slightly in size. So you would need to segregate your brass for each rifle.
You will need a case trimmer after several firings, and lee sells a very simple and effective hand tool and case mouth chamfer tool.
Very inexpensive yet quality little hand tools.
You will obviously need a bullet mold suitable for .30-30 with a flat point, probably 170 grain or 150 grain.
The Lee 2 cavity ones will work fine, and are inexpensive.
A gas check bullet will work best and that's probably all that you will find these days.
Lee also sells a bullet sizing die kit that also seat gas checks, but you need a reloading press to use it.
This is the least expensive and effective bullet sizing option, but works perfectly well.
The bullets are tumble-lubed with Alox liquid lube that comes with the kit and then rammed through the die.
That means either buying a new press, or finding an old one that uses modern shell holders at a gun show.
A Lee el-cheapo C press will work at about $50.00 new. But these are pretty weak in strength and you could probably find a decent old O press like an RCBS JR2 or JR3 (Junior) for 50 or 60 bucks.
But, if you buy a press, you might as well buy a set of dies and also use it to load your ammo, instead of the Lee Loader.
Although, you could use the bullet sizing die alone by clamping it in a vise with soft jaws, and then tap the lubed bullets with gas checks through it using a small diameter steel or brass rod.
That would eliminate the need for the press and work just as well.
Cast bullet hand loads will also require using a lesser powder charge, and lower velocities.
Lee also sells a set of plastic dippers with a sliding charge chart for using them with many different powders and loads.
You should at least read through the .30-30 section of a loading manual for appropriate cast bullet loads.
Or check out various cast bullet forums on-line and look at the many .30-30 loading videos on You-Tube.
You should also learn as much as you can about bullet casting.
I recommend the Lyman Cast Bullet Handbook, which is also a cast bullet loading manual.