I have a Nikon D7000, which currently had a Tamron 18-270mm f/3.5-6.3 Di II VC LD.
This is a neat lens, though sometimes I can see it lacking speed in less than ideally illuminated areas (indoors), and on very long zoomed in pics.
i am planning a trip to Africa next year, and though it is a great excuse to get a different lens.

One similar lens is the Nikon AF-S DX NIKKOR 18-300mm f/3.5-6.3G ED
but I don't seem to gain much with the aperture range, and then going to separate lenses such as
Nikon AF-S DX NIKKOR 17-55mm f/2.8G
and a 55-330, but now it implies changing lenses, and ramping up the money.

So, anyone experienced in wildlife photography, should I keep the Tamron and run it, and just get a smaller lens more suited for indoors? (which seems like the best idea)

Thanks

I took a Canon 7D and 2 lenses to Namibia last summer. A Canon 100-400 and Canon 17-55 f2.8. For me, this was a perfect combination. If you wanted a upgrade in lens, you could go with a Tamron G2 70-200 f2.8 (which I have, great lens) but would likely need at least a 1.4x teleconverter, making a functional f4 lens. I used the 17-55 around camp and for low light and landscape stuff, the 100-400 was used for nearly all the wildlife stuff.

This one was with the 17-55mm

Great pics!

For wildlife without an expensive prime, maybe the Nikon 200-500 f/5.6 or Tamron 150-600 G2.

I'd not worry too much about what continent one might be standing on. Just get a couple lenses that work. For wildlife something in the 100-400 range and indoors maybe 28-135 mm. Not met many that were happy with the extreme zooms like 18mm and out, as they're quite wanting in early and late light when stretched out.

Some of it would depend on whether you are doing any low light activities. I found the 100-400 f4.5-5.6 was fine for the animal viewing we did but I did appreciated have a f2.8 lens for some indoor stuff and shots around the campfire etc

Agreed. That is what I am noticing with the Tamron 18-270.
Duckster pictures are amazing, and seems like getting a 100-400 would be better use of money, as indoors and in controlled situations the Tamron with an aftermarket flash works great.

I have a friend who has the Tamron 18-400. Pretty nice lens, especially in the middle ranges but a bit soft at both extremes. The lizard also taken with the 100-400

The Tamron 150-600 G2 is a fantastic lens. Best in its class. Super sharp, sealed and the best coatings on the market

agree, nice lens but big/heavy