This is a best-of-everything plan to enjoy skiing, barbecue, and a party all in one day trip.
Literal
This [topic-は] skiing [and-と] barbecue [and-と] party [object-を] day-trip [with-で] enjoy best-parts-taking [possessive-の] plan [copula-だ].
いいとこ取り 'cherry-picking the best parts, having your cake and eating it too' — いいところ 'good parts' + 取り 'taking.' 日帰り 'day trip' — 日 'day' + 帰り 'returning.' The plan is ambitious: cramming three activities into one day.