Yes, I agree that both should be acceptable translations although there seems to be a slight preference for "el hogar" to mean "home" and "la casa" to translate as "the house". See what about.com has to say on the matter: http://spanish.about.com/od/translationsfromenglish/a/words-for-home.htm
To me "ample" implies that it has at least a little more than "enough" room. For example, if a woman is said to have an ample bosom, that generally means she has an above-average chest measurement. Also note that one of the suggested translations is "spacious" -- you don't use a term like that for something that's simply "big enough," do you? You might say a house that is spacious and roomy is "big enough," but someone else is likely to say, "that's putting it mildly!"
If I had to guess, amplia refers directly to the actual size and roominess of the house. While plenty could also imply that, it might instead be referring to other things such as cost, or even its roominess relative to the number of people living there: "This one-bedroom apartment is plenty for the two of us right now, but hardly spacious enough if we decide to start a family."
I think that 'plenty' would be a valid synonym for suficiente or bastante, but not here.