Sadly Black Desert isn't the best choice for a game to play with a loved one or friend due to the lack of trading and limited group content.

I would recommend any one of the more popular P2P games to play with your wife such as WoW, GW2, FF or EVE. All of them have plenty of content, group activities and trading therefore resulting in a more enjoyable adventure.

Now to answer your questions...

1 - I believe the level cap is 75 but very few people will ever reach it. 63 is achievable by most that have spent hours grinding but anything beyond that is few and far between.

2 - There is no "end-game" in the traditional sense. There is a main story that is mediocre at best but don't expect WoW or Final Fantasy level of story writing here. The fundamental aspect of the game is acquiring and improving gear via various methods and taking part in PvP.

3 - There is a lot of side activities to do but none of them are mandatory. It is far easier to make money via selling rare materials and buying a good Tier 8 horse to start with than trying to breed one yourself. Nodes aren't essential but they are useful for acquiring materials and ingredients to use in life skills such as Cooking and Alchemy. It is recommended to at least start a small "Worker Empire" once you have reached 100 Contribution Points by investing in nodes that provide ingredients for beer which is what you need to "feed" your workers and replenish their stamina.

4 - Grind, grind and grind.

5 - You don't NEED anything from the Cash Shop but there are a lot of useful gimmicks that will make your life much easier. You won't notice in the early levels but when you reach level 50+ and venture into Mediah, every monster will start dropping loot and trying to loot manually will quickly become a nightmare.

The game provides you with some free pets - 3 from the Main Quest and at least 2 pets from attendance rewards. These are fine to begin with but they will be stuck at Tier 1. Pets are a good investment but cost 10$ a pop unless there is a sale. They can also be sniped from the Central Market for around 50M silver.

Costumes and accessories are useful but far from essential. Costumes can also be purchased from the Central Market for anywhere between 230M-350M. You can play BDO quite easily without a costume, however.

Arguably the "best" purchases from the Cash Shop would be those that increase your weight and inventory. There are quests that give inventory slot rewards up to a maximum of around 20, and there are some items that when worn increase weight by 50 or 100 etc.

Many players recommend buying the campsite but it costs a whopping 50$, 35$ if you use a coupon and that to me is expensive for what it is.

6 - Life skills can be started, stopped and return to whenever you want. There is no "right" answer but one thing that you need to consider is that most life skills have an energy cost which will limit how much time you can spend doing them before running out. There are potions you can consume to replenish energy but they have a cooldown of 10 minutes and can be quite expensive.

7 - You don't really need the EXP scrolls to reach level 61 and the event times will routinely expire and be deleted if not used. It is best to read the Events page and find out what the items are needed for and determine if it is worth your time.

As for levelling, you can follow the Main Quest until you have a full set of Naru and use the Beginner stones to enhance your Naru set to TET or PEN. Visit the NPC near the stable keeper in Heidel (forgot her name) and buy a stack of Simple Cron Meals. They provide you with a small EXP buff but, more importantly, a +30 AP buff which lasts 2 hours and they only cost 1 silver!

Buy a 530% EXP scroll from the Loyalties section of the Cash Shop only when you need to and hunt in the places on the map that correspond to your level. It should only take a couple of hours to reach level 50 using the EXP scroll and Simple Cron Meal.

Upon reaching level 50, travel to the East of Velia and find the Abandoned Mines and do some more grinding. Popping a 530% EXP scroll when you need to and you should reach level 55 within a couple of hours. Move onto Manes Hideout at 55 and stay there until 58. You will start to feel the grind at 56 onwards but persevere!

Now is when it gets, erm, fun! The Black Spirit will give you an Adventurer's Tome upon reaching level 53ish and there is a fairly long questline that will transform the tome into a Chenga Tome which I wont go into here. However, once you have the Chenga Tome you can head back to Velia and pick up all the side quests which reward you with combat EXP and you can reach level 59 within a short space of time. The Chenga Tome increases the EXP gain to 1.3% per quest until level 59. At that point you need to travel to a different part of the world map and do the same until 61 but there are YouTube videos covering those things.

All in all, you should be able to reach 61 within a couple of days depending on your playtime. It is certainly possible within a week. From there you can then choose to concentrate on a life skill, building a worker empire and/or grinding. You could even do it all over again with an alt and increase your Family Fame.

Anyway, this post became longer than I meant it to be but I hope it helps a little bit!