Long time no see/post!
What's your current training like? "moderate weightlifting" makes me think you're probably not getting as much out of your strength training as you could be. Let me elaborate.
I got lazy whilst injured. Still trained but lost my spark. As I started getting back to the heavy stuff, one thing really dawned on me - I was "unfit". Sounds silly, coming from someone who's primary goal is to lift heavy stuff, but it's not. I looked back at pre-injury training logs and couldn't believe how much I used to get done in one session. I wasn't even getting half as much "work" done per session. I lost the fire in my belly and just went through the motions.
Fact is, you need to be "fit" to be strong. If not, you'll hit a wall with your strength. This could potentially be less important if you could train for 3 hours each session but, I doubt it and, who can do that anyway?
Even on the westside site, the elite end of the lifting-heavy-things-spectrum, there's a lot of info and importance placed on "GPP".
The fitter lifter will get more volume in over the same time frame as the unfit lifter. More quality sets, more sets with heavier weights, more volume on assistance exercises. Just more of what they need simply because they are fitter and can recover quicker between sets, work up to heavier weights with less rest, etc.
The same workload done in less time at the very least makes you more efficient and at the most, allows you to get either more assistance, corrective stuff, active recovery stuff, or dare i say, some dedicated conditioning.
I honestly do twice the workload now in the same time when compared to the beginning of the year.
Anyway, failing that, just add a conditioner at the end of the work out. I like circuits with things like - Goblet Squats, Smashes, Swings, Renegade Rows, repeat until death.
You could also just tweak your variables to make your resistance training more cardio focused. For example, pair upper and lower body exercises, such as squats with a press, alternating between them, keeping rest short.
When I speak to people who can't get out of the all too black-and-white mindset that "weights = strength and muscle, cardio = cycling and running", I make them do DB rows with DB step ups with no rest and they see the point almost instantly.
You can get whatever you want out of your "weight lifting", you just need to do it. Your heart and lungs don't know whether your squatting, running, doing cartwheels, skipping or dancing, all they need to do is work hard and often if you want to get fitter.