Hi mate, I am a decorator by trade buy I do the odd custom job on hot rodz and the likes as well.
For the filler, key the surface first if its a big'un. Do this by using a piece of 80 grit and only in the actual damage or else you will be sanding out the scratches for months!
You CAN roll a Landie, the trick is such- use a decent quality enamel or vehicle paint. You can get tiny rollers which we use to roll the corners of walls- bit specialist but the fewer bits you do using a paintbrush the better finish you will get. Use this for places you would use a brush to cut in the edges as much as possible. Get a decent set of roller sizes too.
Follow pretty much the advice given already- make sure you have an EVEN well prepped surface that is as clean as possible.
Dip your roller pretty well to start with, then roll it out in your paint tray until it produces an even layer about the same as you would see when rolling a wall.
Roll the Landie! Do a small bit at a time, say panel by panel, and once it is covered... keep rolling until the finish is even and smooth. It will take out most of the orange peel effect and will dry pretty smooth. If you want at the end, you can rub it down with a very fine grade paper and buff up using a mechanical buffing thingy... Or just buff up straight after the paint is dry. You may need more than one coat I would say aim for 2. You could even add a clear lacquer for extra paint work protection but this is something you really need a spray gun for to apply it properly although it does buff up better depends what finish you want.
IF you want to spray the car, a decent spray unit, hose, gun and accessories may cost you almost as much as a respray anyway. You could buy a miniature gun and compressor which people use for modelling (I use it for a variety of things) which comes up about £180- I think the company with the best deal is called the airbrush company or something similar. You get a compressor with tank, hose, gun and a set of paint carriers and different sized nozzles for under £200! Take you a while to get it done this way though and You would have to take care that the finish was even using such a small gun.
If this is the direction you want to go, again make sure you prep the car as best as possible, clean it 2/3 times using a tack cloth and pre-paint cleaning fluid. If you want to do the best job possible, either get it in your garage if it is big enough or erect one of those pop-up gazebos and cover the sides in clear plastic throw away dust sheets. Clean again and make sure the gazebo area is clean (you will look like a muppet doing this in your street!) you will need a few coats but the paint dries ready for a re-coat within minutes due to how thin the layers are.
If you need any advice etc drop me a PM. Oh a word on masking tape if you are going to use it- don't buy masking tape it is sh*t, buy LOW TACK TAPE or FROG TAPE, it is so much better, you don't get any runs under it and it gives a lovely clean paint edge. if you spray make sure you mask up as best you can, you may think the car is masked up well but the over-spray gets through every nook and cranny and then expands to 5 times its original volume to cover only the places where it is hardest to clean off!
