If you can find a way to eventually do both, I'd start with a handheld thermal. I know a lot of guys don't use them but once you use one for a few nights you realize that you look through it 100x more than you do your rifle scope. Holding your rifle up all night long is extremely tiring.
On a budget I'm a fan of the Pulsar Quantum Lite XQ23V with 1.8x optical magnification for $1,699. The XQ30V with 2.5x optical magnification is nice as well if you need it and right now it's only $1,899. Both of those monoculars are great on a budget. I used the XQ23V along side my Trail XP50 for over 6 months and really enjoyed it. The Pulsar Helion monoculars will have a better image quality but they start at $2,500, so you've got to decide if it's worth the extra $600-$800 to upgrade. On a budget the Quantum Lites will probably suite you just fine.
As for rifle scopes, let's go over the differences between the Trails and the Apexes. The Trails have 3 distinct features that the Apexes do not. Internal video recording, a removable/rechargeable battery pack and WiFi streaming to you smart phone or tablet. Take those 3 features away and you basically have an Apex. The Apexes have the same image quality, just not those 3 bells and whistles. Alternatively, for the Apex you can buy an external video recorder and cable for about $250 and Pulsar has 2 external batteries for the Apexes ranging in run time from 8 hours up to 20 hours. Prices are $130 and $150 respectively and we currently include one for free with every Apex purchase.
The Apex XQ38 has the same image quality and 2.1x optical magnification as the Trail XQ38 and the Apex is $800 cheaper. The Apex XQ50 has the same image quality and 2.7 optical magnification as the Trail XQ50 and the Apex is $1,000 cheaper. At the end of the day, let your budget and feature needs/wants make the decision for you to get the Apex or Trail. If you don't care about the 3 upgraded features of the Trails, then your decision is easy.
As for the XQ38 vs the XQ50 (Trail or Apex, it doesn't matter)....I'm a big fan of the XQ38 for most shots being under 100 yards. I greatly prefer field of view over magnification. A lot of guys on THF disagree with me and prefer the XQ50 and that is perfectly fine, I sell all the models.
I'm used to using the 1.6x of the Trail XP50 and there are many times I wish it had NO magnification. But almost every shot I take is going to be under 100 yards with most being under 50 yards. If you want to take head shots on a nilgai at 100 yards, the 2.7x of the XQ50 is probably a wise decision. I really wouldn't stress over that decision either. Let your shooting distances and budget help make that decision. I don't believe you will be disappointed in either the XQ38 or XQ50, both are awesome.
I've used all of these optics in the field, so I can usually help clear up any questions or misunderstandings you might have about the different models. I hope this helps a little and if you have more questions feel free to call me anytime.