Just one addendum to
@RooFlyer's train comment ... check train prices carefully before assuming anything. I've been making bookings myself of late, and some train trips are a lot more expensive than others; within France for example it looks like the equivalent of a Melbourne-Canberra length trip on the train is similar to the price of Melbourne to Bangkok by air. Switzerland is a lot smaller & has a reputation for being expensive, but it's not looking a lot more expensive than using the Sydney-centred InterCity electric train network.
In answer to the original question about whether it's even possible - I think the Christmas timing will make it unlikely.
Without the Christmas timing I think you'd need to use those bonus offers for getting new credit cards where they give you 150k-ish points for starting the card & spending money on it within the first 3 months (but that money is pretty easy to spend on groceries & other normal stuff you'd buy anyway). If this is for a couple, I think it might be hard to get enough points based on card purchases if you only have the one card - I think that unless you have a (non government) job where you're flying a fair bit, I think you might be borderline. If you each have a card, that gets you more bonus points but make sure you spend enough monthly to get those bonus points on BOTH cards.
If this is for a family ... I mean do some calcs, it'll depend on the bonus points offers available, but I don't think it'll be possible unless you have a job where you're flying a fair bit.
These points-bonus schemes are almost never available on free cards, so probably budget for at least $100/mo just to have the card, the ones with the ~150k point bonuses may be more. Some of those schemes only have a requirement that you keep the card 6 months to get the points, so in theory you MIGHT be able to go through a couple/few cards before you need the points - if you can achieve THAT then you should be sweet (for a couple), but you'd need to be lucky enough that the offers come-up at the same time.
If the both of you collect the points, it's double the spend on credit-card fees of course, but there's more chance of a bonus points offer coming up at the right time for one of you to take it, too.
Of course be aware that if you're paying $100/mo for a card, in two years you've paid for an economy class ticket or for half a premium economy ticket just in fees - and just paying $$ for a ticket you'd have more choice about when you fly (eg. at Christmas).
