There were some key very important starting points for this challenge, starting with traits:
Ambitious - for the extra LTH points
Workaholic - for those hours where my sim no longer needed to eat/sleep/shower and all the tourists had gone home
Innappropriate - so that my sim could go up to just anyone and kiss them, thus making them automatic romantic interests
Charismatic - so my sim could spam ++ social interactions to make fast friends
Schmoozer - helped where there were no ++ options available, with 'praise' and 'flatter' being super fast + socials.
I started with flirty on my trial, but master of seduction makes that unnecessary.
LTW - super popular - he needed to be at least 'friend' level with tourists to woohoo, so super popular fit in with what he was up to anyway.
Next, timing was important. It was necessary to complete his LTW on the morning of day 1 and to acrew as many LTH points as possible. So he took a job, then met as many people as he could before 11:00am and headed off on vacation. On vacation he learnt charisma, then met the rest of the male population until he had 25 aquaintances for the charisma challenge, and an instant starting relationship bonus. Next, he met all the local women, explorer women, and tourist women, making friends with each of them as he went. As soon as he had enough happiness points, he bought the observant LTR which helped him to have more ++ social interactions.
Soon he had completed his LTW.
LTRs and their order played an important part in this challenge too:
Observant - more ++ interactions for faster friends
Attractive - combined with the celebrity challenge for charisma = instant friendship status
Fertility treatment - clearly my sim wanted as many kids as possible. This one is a no-brainer
Master of Seduction - when my innappropriate sim kissed people he had just met (and obviously instant friends with) they did not reject it and were instantly romantic interests, available for woohoo.
After that were the not so important 'multitasker' - seems to make working from home more effective aswell as when at work; and then finally the motive mobile.
By the time my sim arrived home just ahead of the first influx of tourists, he had completed his LTW, and had the first essential LTRs and charisma challenges completed, so the scenario went something like this:
Hi, I'm Sergio, you new to these parts? Just visiting? Great, lets kiss! Hey, I have a tent here, fancy a little hanky panky?
The tent which he bought while on vacation was another major strategy advantage. He could take it and woohoo anywhere. However, that stupid strut got to be a real pain, slowing things down, and public woohoos have a tendancy to get your sim in trouble - a lot, losing friends left right and centre, and landing your sim with the publicly disgraced moodlet and lost friend moodlet. So, if he woohood in public, I planted the tent right next to the road so he didn't spend all day marching out to the taxi to go meet the next tourist.
Next of course, it was important to phone in and take as much unpaid leave as possible. As soon as it was available he to 5 days leave at a time.
Every day, even on work days, he invited the maximum 8 foreign visitors. But 8 was not the daily limit, NO! He'd take them all to visit the closest community lot, leaving one at home, then one by one, knock them up and send them home, pop back into the tent, and summon the next one. He didn't even have to leave the home lot to do this: simply relax, and click on one of his visitors, and choose 'try for baby' and they came running. It was important to keep the camera on the visitors otherwise the game sent them instantly back home without notice.
Come 12:30ish, tourists start showing up as well. He'd then spend the next few hours concentrating on the additional tourists, before going back to his visitors at 4pm.
On work days, he'd simply wait for his visitors to turn up and bring them to work with him, late.
Once he had the motive mobile, he spent the wee hours of the morning working from home, so that he could ask his bos for promotions and raises. It didn't get him very far - only lvl 8 - but the real focus was on the kids.
The other trick I used was to constantly have the stereo next to the tent playing kids music. At home I left the tv on the kids channel too. I'm not sure if just listening to the kids channel helped - it seemed to - but just to be sure I got the last visitor of the day to watch it for a few moments with my sim. Combined with the fertility treatment, this gave me a much higher chance of twins and triplets for every woohoo.
I think that covered most things. All in all it was a fun challenge, enjoyable only really micro-managing 1 sim!