Concerned about walls with Wireless

[ninethreeeleven]

Okay my parents house (where I live at the moment) is pretty large. The main computer is in the back room and my room is at least 75 feet away (shortest point) but there is a bathroom and a chimney in the way. Here is a quick sketch of the first floor layout (second floor is pretty similar, only differences are in the top right corner and dont matter)

Do you think I will have trouble with interference here, or should I save the money and just get a router and cables (I can run under the floor to my room, computer 2) I can then go up to the room which will hold computer 3. It wouldn't be that hard to do this (not to mention a crap load cheaper) but my father is interested in getting a wireless router.
I wont be living here in a few months and then will have a wireless card that I wont be using.
Any ideas and advice would be greatly appreciated.
Also if you want any more info I'll get it.
And if you think I should go wired can you recommend good router and wiring (or is it all the same)

-9311.... knows nill about networking.

EDIT: changed pic

 

[unhappy_mage]

i'd suggest wired, because a) it's cheaper and b) wireless might have problems. i work with n00b networks all the time, and the wired ones are more secure, and less can go wrong with them.

also, for the love of god use png! 850k is way too big. have pity on my 56k.

 

[ninethreeeleven]

my bad, never thought about that, jsut figured MSpaint would be a tiny tiny file...

Pic has been updated from 843KB to 5.45kb

 

[nonsequitur]

i don't have a wireless set up yet, but would it be checking to see if a cordless phone works through those walls? i'm sure a computer would be more sensitive to changes in signal strength, but it might be a worthwhile proxy, if you have a cordless phone to try it out with.

 

[ninethreeeleven]

My cordless phone base is located right next to the stairs in that pic, and works fine in all areas of the house except about 10 feet outside in the back yard, after 10 feet your on your own. Also my cell phone works in all area's of the house except the basement. I'm just worried about stupid stuff messing it up. I dont want that increase in cost, only to find out it doesn't work. All computers already have Lan cards in them so there is saved cost (going wired). Also this house is old (at least 85 years) I dont think there is, and really I hope there isn't, but there may be a nice layer of lead paint in these walls. Good for snacks but what about reception?