And these quests really are like a mini, knowingly silly Tomb Raider. You push blocks around, you open hidden doors with floor switches, you try not to walk through fire and electricity traps and you collect coins and relics. Oh, and you pitch that wonderful tent if it's getting late, as getting back to Base Camp can take an age.
The tomb runs require you to firmly hold the hand of your Sim, giving him to-the-letter directions - taking direct control in a way the game has never previously required. It's a little fiddly, as The Sims is naturally more geared towards broader gestures rather than such precision, but it's ever so charming - and it's genuinely doing something new with the game.
It's light puzzling and light role-playing, very carefully implemented in such a way that it won't confuse or terrify the Sims' less game-savvy audience. Perhaps it's even a gateway drug to more traditional games. As well as earning you money and items, tackling quests wins Visa Points - necessary to extend the length of your holidays, which are initially brutally short.
It's in the small ways that this melds with The Sims 3's marvellous ability to create ad-hoc vignettes that it really shines. My Sim had traipsed through a Chinese tomb, suffering a near-death experience with a firetrap halfway through. Upon finally emerging into fresh air, I duly ordered him to head over to the buyer of rare goods in order to spend all the ancient coins he'd collected.
What I forgot was that a) it was about 3am in-game at that point, b) I hadn't ever met the buyer of rare goods yet, and c) the firetrap mess meant my fat, bad-tempered Sim was now virtually naked and caked in ash. The second this frightening apparition turned up at a stranger's house in the dead of night, they fled - a screaming, arm-waving Chinese merchant running away from his own house in absolute terror. A beautiful moment, and excellent proof of how smart and complicated The Sims 3 can be.
As a statement of intent about how The Sims 3 is going to treat its expansion packs, it's bold and promising. This isn't pets or restaurants or H&M clothing packs: it's a clutch of completely new ideas and mechanics. Yeah, there's a bunch of new skills for your Sims to learn (photography and booze-making, most notably) and home furnishings to buy too, so World Adventures is hardly going to stumble and fall if the audience doesn't take to the quest-and-puzzle stuff after all. But it's enormous, both in terms of virtual landmass and things to do - which is what the game really needed.
The trouble is that it does feel at odds with what The Sims is. It's got no relation to suburban reality, or even to expensive holidays - it's off into Indiana Jones territory, in an entirely different game universe bolted onto the side of the familiar one.
Your Sim pops off to do all this fantastical stuff for a few in-game days, then he's pinged rudely back to normality and there's a disjointed sense of playing two separate games that have been stitched slightly unnaturally together. Though at least you get to take the tents and Showers In A Can home with you.
On the other hand, now EA has taken the step of making your Sims' activities more interactive, hopefully that'll be retroactively inserted into the main game/towns in a future expansion. As well as filling in a few of the parent game's holes, it'd make 'The Sims 3 plus World Adventures' experience a whole lot more seamless.
Without a doubt, EA isn't treating the expansion of The Sims 3 lightly - World Adventures might be a bit of a thematic stumble, but it makes for a significantly bigger and more varied game, far more so than any prior Sims 1 or 2 expansion has achieved. It's impossible not to recommend it to avid Sims players, but anti-Sims snobs will inevitably find it to be an annoying side-order of collectormania and repetitive puzzles.
If some of its interactivity mechanics can eventually be folded into the game's core open world, however, then we'll be well on the way to having the pacifistic Grand Theft Auto it's surely this series' destiny to ultimately become.