Re: level advancement & treasure in older D&D/AD&D - this really depends on what you use for your baseline assumptions. If you do what a lot of people did --ie use the tournament modules that were adapted and published for home campaign play -- leveling was quicker, because they contained a *lot* of treasure & magic. If you use the tables in the back of the DMG as your guide, your results will be different (though I should note, the tables in the back of the DMG don't produce the, ahem, wealth density found in the classic AD&D published adventures, up to and including the magic item load-outs found in your average pre-gen PC).
For my (somewhat) recent foray back into AD&D, I used *parts of* a few classic AD&D modules, and that yielded a significant amount of cool bling and heaps of money. In 2.5 years the party went from levels 2-3 to 8-9. Which proved to be a satisfactory amount of advancement, even for a group that had played 4e and 3e as their previous long-term campaigns.
For my (somewhat) recent foray back into AD&D, I used *parts of* a few classic AD&D modules, and that yielded a significant amount of cool bling and heaps of money. In 2.5 years the party went from levels 2-3 to 8-9. Which proved to be a satisfactory amount of advancement, even for a group that had played 4e and 3e as their previous long-term campaigns.