Do a mini mash with 2-row and add the pumpkin to both the mash and boil. It's a win-win.
If done properly, the pumpkin will yield body, flavor, and aroma. This will be especially evident with fresh roasted pumpkin, seasoned during cooking (not after). I like to cut the pumpkin with a bit of butternut squash as well, which adds some complexity of flavor yet still keeps the theme.
Toast whole spices and grind them fresh; get your ratios right since too much of a certain spice might dominate the beer's flavor. Try not to make the beer too dry or highly carbonated. Pumpkin beers taste a little weird when they're too dry and too fizzy. I like them middle of the road; not too sweet/not too dry with low to low-moderate carbonation.
This type of beer works way better when brewed via 100% All-Grain since you can layer it with a variety of complimentary specialty grains and mash the majority of your fermentables, which allows you to control the overall body and FG a bit more.