What is the easiest and most economical way to finish an interior ceiling?

I have a house built in 1948--huge house. The two upstairs rooms have the old wafer board ceilings ripped out, leaving oak boards, unfinished, rough, and uneven. What is the easiest way to finish the interior ceilings cosmetically, thinking economically and ease of labor, as the wife and I are older and have limited stamina. Would be happy with just a paintable waferboard or something like that. Insulation is not a problem, as it is insulated above the oak boards. Ceilings are also low, so suspension ceiling is not an option. Am thinking some type of glue up--but have to make it flow out as the boards are really rough with up to half inch vertical space between some boards. Can not hang drywall--could if I cut it in small pieces and hauled it upstairs.--then the problem of taping and wall mudding the seams. Sugggestions would be greatly appreciated. also if responding, please let me know where to buy the materials. Thanks.

try beaded board 8X4 ft sheets with trim to hide seams. turns out great.

Not sure if this will help at all....but I am in a similar situation, except it is an older model mobile home that needs pretty much EVERYTHING redone. If you know of someone who goes to auctions for surplus building supplies, you will probably be in luck. There is such a person in our area, and he gets surplus or leftovers from all sorts of places (especially mobile home manufacturers). Anyway....he gets pallets of paneling that have "wall-paper" on one side. It's not sheetrock like in most mobile homes today. It's more like luan or actual paneling. We can get sheets (4x8) for as little as $2 each. We are going to buy an entire pallet, and use the paper side for our interior walls, and the wood side for the ceiling and flooring underlayment. Then we are going to put "beams" at all of the joints in the ceiling (more than likely just some cheap spruce 1x3's) and then prime and paint. For our entire house, it is only going to cost us about $400. That's ceilings, walls, AND underlayment for the ENTIRE thing...every room. If you don't know of anyone that does that, you might be able to find paneling or luan at a discout building materials type of place. Even if you have to go to somewhere like Lowe's or Home Depot, their luan is only about $10-12 per sheet depending on where you live. Anyway, it's lightweight, and easy to put up...just a thought. Hope this helps.