I would like to remove the old 1970's paneling on the bedroom walls... it has been up for 35 years. Then I want to paint the walls. Is it going to be a hard job to clean the walls, sand the walls, then paint them?

You have a number of issues.

First there might not be anything behind the paneling (other than studs).

If there is DW the paneling might have been glued on and removing it will take off chunks that will hve tobe repaired.

And unless the paneling a DIY over exisitng drywall then the door and window trim will be OVER the paneling and it will have to be moved and replaced.

If the paneling is solid and sound you can paint it. But the groves will show.

To do that wash it with TSP. Then go over with a deglosser ("liquid sandpaper").

Then a good sticky primer. I one that I like is Bullseye 1-2-3.

But a Real Paint Store will might have other suggestions.

Thank you for your help... there are glue marks all over... ugh!!!!