Is there such thing as an industrial sander for decorating?

Drywall sanders are specifically made to sand chalky substances that turn into a powder and fall to the floor or get sucked up. Paint will clog them up and make them useless. I'm afraid there is no quick fix for your house. Removing the trim, numbering them, stripping them down with chemicals or by hand, or replacing them may be your best option. This can be done over time as you live there. If the walls need to be done prior to moving in, You can sand down any bumps and skim coat the walls using a wide taping knife. I do three coats, first one vertical, second horizontal and third one vertical again. Then a light sanding with the drywall sanding pole and your ready for primer and paint. Look on youtube to learn about any of this.

just use an electric orbital hand sander. you just need to rough up the surface a little,

you don't need to sand down to the drywall. when you repaint you can use a product

called KILZ it will prime the surfaces and make the new paint stick.

It sounds like you need a "palm sander". This is a hand held sander that takes sand paper which happens to be the width of most woodwork. Sanding paint that is in an old house may be a lead paint hazard if the house was built before 1979. In that case, it is best to just use a paint deglosser on the painted areas to dull the sheen in order to paint with a fresh coat of paint.

Again, if you really want bare woodwork, it can be done, but it is a lot of very hard work. I would suggest that you just paint all woodwork either white or off white and paint the walls the color you want after deglossing the current surface. Deglossing is needed in order for sheen to be removed so the new paint adheres.

Vinyl silk will lift off with a wallpaper steamer

All you need to do to prepare gloss paint for painting over is to clean and lightly abrade the surface. If you use a strong alkaline detergent (sugar soap in the UK) and a nylon pad scourer it will do the job reasonably quickly. Wear rubber gloves. With painting it's preparation that counts, not speed. So do the work piecemeal. That is manageable areas at a time. Repaint these as you go which will give you a lift.

You don't say what age your house is, but as paint used to contain lead (especially if it was white) sanding is a bad idea. The best thing is to use a heat gun and properly done it will strip off the old gloss paint back to the bare wood.

People do not sand paint, except sometimes a light scuffing of a gloss paint on woodwork or cabinets or furniture. It is not done on painted walls. If you want to cover a paint you don't like, then you fill holes and dents, prime, and paint. If you sand a drywall wall, you stand an excellent chance of sanding into the paper covering and that damage is almost impossible to disguise. Drywall sanders are for sanding the mud used to cover the joints of drywall walls, and for sanding patches, not for sanding a whole wall.

No. It will take scraping with a scraper and probably minor patching, then smoothing with a belt sander. That is what I would .do. The drywall sander of a pole id for very minor touches.

You might be better off just painting. Latex paint with a long nap roller should be able to cover just about anything, especially a premium grade latex flat paint. If you need to change the roughness of the surface, add some texture into the paint. You still have a big paint job. The easy way is to hire a painter with a spray gun to paint it. He can probably give you some advice, too. If you do it yourself, and the house is empty, figure about 5 days per room to paint everything. A room will have 3 colors in it, ceiling,walls and casing. That involves taping the finished wall to paint the casing. And you will have to paint all the corners with a brush to use a roller on the ceiling and walls. The fastest and easiest part of it all is painting the wall. You will also use about 3 times more paint than per the coverage area.

liquid paint remover -- see your hardware or home improvement store