Each tent requires the same amount of space, the only difference is in the quality of rest. After a good night's sleep in the tent from the Special Merchant you get a "Slept like a King/Queen" moodlet.
I've completed this wish, so what I can say is:
Most importantly: You need to search for the right adventures!, 'cause there are some referring more to the lifestyle than tomb-exploring, some are purely run-errands type. Each gives you visa points, ancient coins and simoleons. Even though I did take up the challenge and groomed a Sim who is a formidable cook, gardener, fisher (it all goes together, right? especially if you're a single Sim) and nectar maker, if anyone wants to quickly finish this LTW, they probably should avoid those time consuming activities.
-*Always* go on your own.
-Immediately buy the better tent - no point in buying the small one, the better the tent, the more time you've got for exploring.
-Shower in a Can - lots of it for firetraps/signed etc.,
-High Quality Dried Fruit - you wouldn't want your Sim to eat low quality food for days, right?
-The Hours Tear would be the first item I'd spend my money on next time I have an adventurer in my family, because it's helpful with collections, and spares you opening some of the chests where there are only coins which you don't need as much later. The next would be the tent.
-Start in China up to the moment when you get Pangu's Axe, take your time to learn martial arts, it'll help with the mummies.
-If you're scared of mummies, you should spend sometime with the snake-basket. You can purchase it in Egypt.
-*Don't* buy an expensive vacation house, which usually are mansions outside of town unless you're curious about the inside. The closer the location to the base camp/town center the better. Less time spent travelling.
-Maybe not in China or Al Simhara which aren't vehicle friendly, but in France you can save time by having a fast means of transport.
About "Athletic"... I think it's a waste of time to build it up. I've been through 6 tombs, and it got me from 0 to level 8 athletic skill. Better get started on looking for those hidden doors.
And handiness might be a good idea, but I wouldn't say it's connected with traps.
I don't know if it'll be the case with other people, but since I was doing a lot of adventures, when I accomplished my Life Wish I had level 3 visa in China and France, and on the next trip after I explored the 6th tomb I had level 3 visa in all vacation spots, so I could've chosen the other one instead, because it's a lot more point-rewarding.
-Adventurer is a good trait, because it makes your Sim happier while he's sleeping underground or when you're trying to figure out the combination to rebellion HQ.
-Prepared traveler will give you some extra time, and the certificate of partnership with any country too - but you need to be a level 3 visa to buy it, so it doesn't help that much.
About Martial Arts:
One adventure string requires you to master it and win the tournament. do both at the same time by sparing with your tournament opponents, so that when the time comes you won't be bored getting the tournament ranks. It's an invaluable skill when fighting the mummies.
Since a lot of the people were victims of the out-of-the-blue foreign families, myself included, untill EA manages to fix the bug*if* you want your Sim to have a proper wedding, you had better do it before running off to explore the tombs. In other instances you might want to always save before going on vacation, and check your Sim's family tree for any unknown foreign offspring. when you arrive at your destination and return home.