Congrats, I think that colour combo is probably THE best for a Boxster and the low mileage is nice. I buy all my Porsche parts from Sunset since they're the cheapest
I think you could drive it home in 2 days- 70mph most of the way and 80 in Nebraska and Wyoming (?) but weather could be a real problem- there's a mountain pass in Oregon (I84) and then the open plains thereafter. If the long-range forecast is good than I say go for it! A breakdown seems VERY unlikely.