All right, I have been working toward the quest cape for about 2.5 years now and I constantly get told they're really simple to RS gold get. Much easier and faster than many, or even all 99 skills, depending upon the person telling me. I got told that today, and I was quite bored, so I decided to do a few calculations. Simply adding up the solid skill requirements that you need, it comes to 11,492,440 experience. That is just equivalent of just below level 98 in any 1 skill. But wait a moment, there's a level 85 battle requirement too. The skill requirements only state 40 attack, 65 defense, 69 strength, 55 prayer, 75 magical, 75 ranged, and 41 summoning. That brings the entire minimum xp into 12,030,092. To be fair, in case you've got 65 defense and 69 strength and 75 triumphed, you're likely going to have absolutely no less than 65 attack and 70-75 hp (depending on how you train). That brings the probable total to between 12,641,117 and 13,113,911. It is likely to get it at this level, however, so we'll leave it there and give ourselves a conservative estimate.
Recall a 99 in any ability is 13,034,431 xp. I contend that the coaching to get a pursuit cape is as hard as most 99's. Quite somewhat harder even, if you consider that the majority of that training is in the lower levels. Compare it to training to 99 range in f2p. It's much, much harder to get 13M xp with no advantages of things that open up in greater levels that member skillers so often take for granted. No, you need to really do the quests! Let's perform a rough estimate a second. There are 159 quests, so they probably take an average of an hour each if with a manual (they do for me anyway). Even when you're a diehard RuneScape player and play 4 hours a day 7 days a week, it'll still take you 5 weeks and 5 days to complete them all. Now assume an average of 10 minutes between each person to get prepared for the quest, that bumps it around 6 months and 5 days. Just doing the quests after you have all of the training done takes more than fletching or cooking! That actually makes it seem shorter than it really is. If you are more like me, and play about 7 hours each week, it's going take 26 weeks and 4 days, or about 5.5 weeks.
Of course, there will be the smaller details, such as 10 of their abilities being boostable to get the maximum required levels, but I believe that only partially compensates for the quests that you'll likely want to be substantially above the required level. There is also the chance of dying and losing significant amounts of money which makes things tougher, but it does not take place if you're smart (I've lost a total of about 225k in a total of about 3 deaths on quests). And we're completely ignoring the time necessary to make that money, but in my situation I haven't had to spend any time earning money, so long as I go without things most people have, like whips. Oh, and Jagex keeps releasing new quests, fairly often increasing the skill levels which you need to cheap RuneScape gold obtain, so the pursuit cape keeps getting harder to get, where abilities only get simpler, if they change at all.