1. You have to trade for the same season you purchase.
No. You must reserve a week to use or to exchange in the season you own. But you can exchange into any week at any resort that II deems to be a "comparable exchange" (more on comparable exchanges later). The "seasons are designated by Marriott for sales and reservation purposes. They have no specific significance for exchanging.
Some Marriott resorts have a single season (usually Platinum) and others have as many as five seasons, including one or more fixed week seasons. See
this link to one of the FAQs for this forum for more info on Marriott seasons.
You should also look at the other FAQs (located at the top of the list of topics for this Marriott forum) to learn more about Marriott timeshares.
3. To trade for other seasons by buying any Marriott gives you and advantage in II for seeing other Marriott before other people
Yes, it does. But that doesn't mean you'll get the trade you want. For example, assume you buy an off-season (e.g., Silver) week at a Marriott resort and want to exchange into Hilton Head's Grande Ocean for 4th of July week. It's likely that other Marriott owners who have deposited with II weeks that are more in demand (e.g., high-demand Platinum and Gold weeks) will get those great G.O weeks.
That's because II generally confirms exchanges on a comparable exchange basis. “Comparable exchange” means that the two weeks are reasonable comparable considering a variety of factors including location, time of year (holiday, high season, etc.), how far in advance you deposited, how far in advance you made your request, how much in demand your week and the week you want are and how many of the weeks that you want are deposited by their owners. The higher the demand is for the week you deposit, the more likely it is that II will deem your dream vacation request to be a comparable exchange and confirm it for you.
However, if you can travel to resorts when it's off-season at those resorts, a poor trader might well suit you. Trying to keep your purchase price under $3,000 probably fits in that category. Don't make the mistake of buying an off-season Marriott week if you expect to trade to top resorts in peak season. You'll get lucky occasionally, but it won't be something you can count on.
4. Is it better to buy outside Orlando. Because Orlando is easier to trade in to.
I would buy outside of Orlando for two reasons.
First, most of us would usually recommend that you buy where you would be happy vacationing at least every other year or so. That's partly because requested exchanges are never a certainty. Whether the week you want will be confirmed depends not only on the comparable exchange criteria, but also on whether owners of the weeks you want deposit enough of them for you to get a confirmed exchange.
Second, you hit it right. Orlando is relatively easy to trade into. So buy a week in another area where you would be happy vacationing. My guess is that wouldn't be in the Orlando area, since you live there.
5. Is a lockoff a good deal, as you can trade the lock off portion?
Yes, a lockoff allows you to deposit each portion of the unit and confirm two separate weeks of vacation.
6. Is there any advantage to picking home resort if you will mostly being using it for trade. I've look at Desert Palms, Hilton Head, Branson
See #4.
7. Why is Colorado (Vail) so cheap sometimes
StreamSide is an older resort that has some weeks (e.g., "Preferred" season) that are not attractive to most vacationers. How many people want to vacation in the mountains when ski season is over, school isn't out yet and it's still too cold to enjoy the beauty and activities of summer? Those weeks would likely be among the worst traders in Marriott's portfolio.
That's true of other Marriotts, too. If you buy an off-season week, likely necessary if you want to spend under $3,000, you'll probably have a weak-trading week.
